L8 1004 - Cognitive and Emotion

What does affective mean?

relating to moods, feelings, and attitudes.

To investigate the role of the amygdala in the facilitation of attention, the emo-tional salience of the second target word was altered. When the second target word was an emotional, arousing word, participants were more likely to report it (Anderson et al., 2005). In other words, emotion facilitated processing and decreased the atten-tional blink. Consistent with the "face in the crowd" studies reported earlier, this re-sult suggests that when

when attentional resources are limited, emotional stimuli reach awareness more readily than non-emotional stimuli. This study was also conducted with patients who had suffered damage to the amygdala (A. K. Anderson & Phelps, 2001). These patients showed no difference in the attentional blink effect for emo-tional words versus neutral ones, which offers further evidence that the amygdala is modulating this enhanced awareness for emotional stimuli.

5.3 Mood and Memory Mood reflects a lasting and diffuse affective state that is not necessarily linked to any spe-cific event. Have you ever noticed that

you are in a bad mood, you are more likely to recall negative and unfortunate events, whereas when you're in a good mood, happy occurrences come to mind more readily? This common experience reflects an influence of mood on memory known as the mood-congruent memory effect (Bower, 1981).

5.4 Memory for Public Events In a study designed to discover factors that may be related to accuracy and confidence for memory of emotional public events, researchers examined memory for the 0. J. Simpson murder trial verdict in 1995, a "hot-button" political and social event for many people (Shmolck et al., 2000).

A little more than a year after the verdict, respondents were still fairly accurate in their recollections of the personal details surrounding the event (where they were, who was with them). After three years, however, many showed significant distortions in their memories. As in the Challenger study, all respondents, including those whose memory was faulty, gave detailed accounts of their experience and were confident of their accuracy. In the Simpson verdict study, the only factor that emerged as predicting better accuracy af-ter three years was the level of emotional involvement of the respondent at the time of the verdict. Those who reported higher levels of emotional arousal to the verdict had more accurate memories for the event when questioned three years later. These results are consistent with the idea that higher levels of arousal (at least up to a point) may help guard against some distortions of memory.

5.4 Memory of Public Events Although memory for emotional public events is often inaccurate in detail, it is nonetheless long lasting and compelling. The respondents in the Challenger study re-membered that the event had occurred; their inaccuracies concerned their own con-nection to it. Similarly, although many people are confident that on September 11, 2001, they saw television pictures of two planes striking the World Trade Center (Pedzek, 2003), they couldn't have: no video of the first plane was available until the following day. (A moment's thought will suggest why: no television station, network or otherwise, was photographing the buildings that morning before the first attack-they had no reason to. Video of the first plane came from another source, and it took a certain amount of time before it was available.

Again, people obviously remember what occurred, but have forgotten details about their connection to it. Nevertheless, iconic images of emotional public events-John Kennedy smiling in an open car mo-ments before the shots, the heartbreaking arc of the damaged Challenger against the blue sky-the image of billowing smoke from the World Trade Center (Figure 12) have left a lasting impression. Some large-scale studies are under way examining memory for the World Trade Center disaster (Begley, 2002). These studies should help clarify whether, as Brown and Kulik (1977) proposed, special mechanisms exist for the formation of memories for emotional public events or, as the results from the Simpson verdict suggest, these memories are the result of ordinary memory mechanisms, likely interacting with arousal. It is clear that the recent advances in our understanding of the influence of emotion on memory will help us interpret results from these studies in light of both cognitive and neural mechanisms.

6.1 Emotion and the Capture of Attention Emotion captures our attention and makes it hard to respond to nonemotional stimuli. This was demonstrated in an emotional version of the Stroop test, a classic measure of attention.

As in the original version, participants are presented with words printed in different ink colors and asked to report the color of the ink and ignore the words. However, in this modified version the words are not color names but either emotional words (for example, rape, cancer) or neutral words (for example, chair, keep). When the words are emotional, participants find it more dif-ficult to ignore the words and name the color of the ink (Pratto & John, 1991).This effect can be exaggerated for stimuli that are specifically relevant to a given person, such as the word snake for someone with a phobia for snakes (Williams et al., 1996).

Mood is related to attitude and motivation What is attitude?

Attitudes are rela-tively enduring, affectively colored beliefs, preferences, and predispositions toward objects or persons, such as like, love, hate, or desire for a person or object

What does cerebral assymetry

Cerebral asymmetries refer to structural and functional differences between the two brain hemispheres.

5 Emotions and Declarative Memory

Day to day, we tend to use our memory to answer questions such as "Where did I leave the keys?" But on the scale of a life, your lasting memories are not of the pocket in which you left your keys. Memories for events that are emotional and important seem to have a persistence and vividness that other memories lack. Memory for emotional public events, such as the destruction of the World Trade Center, will persist, although imperfectly. Memories for emotional private events, such as the birth of a baby, also are imbued with special qualities. How, exactly, does emotion influence memory? One of the primary advances in memory research during the past 40 years has been the growing recognition that memory is not a unitary concept: different forms of memory, conscious and unconscious, relate to different neural systems. Declarative memory is long-term memory that can be consciously recollected and described to other people. It includes episodic memory, the "first-hand" memory of our own indi-vidual past histories, and semantic memory, knowledge about objects and events in the world. Both forms of memory can be influenced by various aspects of emotion in several possible ways.

4.2 Instrumental Conditioning: Learning by Reward or Punishment Emotional learning can occur when certain actions and stimuli are paired with reward or punishment. Take, for example, gambling.

For a gambler who bets on horses, actions such as going to the racetrack and placing the bet, and stimuli such as the racing pages and the morning line of probable odds, are paired with reward if the player wins. Although the bettor may lose (punishment), part of the reason gam-bling is so appealing to some people is that the thrill and excitement of an occasional large win is often more powerful than the many smaller losses that may occur.

2.2.1 Circumplex model The dimensions of arousal and valence may have distinct representations in the human brain. For instance,

For instance, one study examined brain activation patterns that result from the presentation of olfactory stimuli (A. K. Anderson et al., 2003). The amygdala responded primarily to the intensity of the smell whether it was pleasant or unpleasant to the participant, whereas different subregions within the or-bitofrontal cortex (OFC) responded when the smell was either pleasant (medial OFC response) or unpleasant (lateral OFC response), regardless of the stimulus in-tensity. These results suggest that the amygdala, which also is important in our perception of expressions of fear in others, may code several different aspects of emotional experience.

Another study seeking to determine whether the amygdala modulates the facili-tation of attention with emotion made use of the phenomenon known as the attentional blink. The attentional blink is a brief loss of attention that occurs when a second visual stimulus appears very quickly, perhaps a few hundred milliseconds, after the first one (Chun & Potter, 1995). (Proofreaders must guard against atten-tional blink, or they will miss a second error that falls soon after an earlier one.) An attentional blink test might employ a string of 15 words as stimuli that are presented very quickly, about one every 100 milliseconds.

If the experimenter tells participants that they only have to attend to and report two of the words, which are printed in a different color of ink from the rest of the words, participants are generally success-ful-unless the second target word is presented soon after the first target word. It is almost as if noticing and encoding the first target word creates a temporary refrac-tory period during which it is difficult to notice and report the second target word. It is as if attention blinked.

3.3 Measuring Emotion Directly How would you know whether you were being successful in your attempt to console a sad friend? You might simply ask: "How are you doing now?" Or you might look for an emotional reaction, such as a smile or the end of tears. Probably the most common technique used to assess affective states or responses, both inside and out-side the laboratory, is self-report.

If we want to know how someone feels, we ask. This is a form of direct assessment, in that participants explicitly report their emo-tional reaction, mood, or attitude. Although this is an often-used method for assess-ing affective states, it relies on introspection and is affected by cultural conventions. Therefore, it is important to have a way to measure an affective reaction by indirect assessment, that is, by means independent of subjective report and language.

6.2 Facilitation of Attention and Perception Emotion can capture attention and impair performance on a task; and, as we see in this section, it can also facilitate attentional processing. How is it that emotion can both impair (or "capture") and enhance (or "facilitate") attention? The effect of emo-tion on attention depends on the specific demands of the task.

In the studies consid-ered so far, successful completion of the task required the participants to focus on and process the nonemotional aspects of the task; in the emotional Stroop task, for in-stance, participants are told to ignore the content of the words and to process the color. The attention tasks that demonstrate facilitation due to emotion usually require the participants to respond to or process the emotional stimuli directly or to respond to or process a stimulus that is cued by emotion.

2. Defining Emotion What is mood referring to?

Mood, on the other hand, is used to refer to a diffuse affective state that is most pronounced as a change in subjective feeling. Moods are generally affective states of low intensity but relatively long duration, and Emotion and Cognition sometimes without any apparent cause, such as a spontaneous feeling of gloom or cheerfulness. Two related concepts are attitudes and motivation.

1. The Connection emotion could be experienced without cognitive appraisal (i.e., an in-terpretation of the reason for your feeling). Question One side was research showing

On one side was research showing that emotional stimuli presented subliminally (unconsciouslly), without the participants' awareness, nonetheless influenced the way participants evaluated subsequent neutral stimuli (Zajonc, 1980, 1984)

3.4 Measuring Emotion Indirectly First way of indirect assessment of emotion

One way of making an indirect assessment is to ask the participant to choose among different options on the assumption that an emotional assessment of the options partly determines the choice.

2.2.2 The Approach - Withdrawal Distinction Davidson et al. (2000) have provided evidence that there is a cerebral asymmetry in the neural rep-resentation of approach and withdrawal tendencies. Using EEGs, these investigators found that participants varied in the relative level of activity of the anterior left and right cerebral hemispheres when at rest, and linked this asymmetry to their various FIGURE 4 40 ~ 30 § ~ z ct 20 D Left anterior frontal D Right anterior frontal 10 A . I pproach W1thdrawa Type of trait Participants with greater activity in the left anteriorfrontal region at rest (measured by EEC) rated themselves as higher on "approach" trait s such as enthusiasm, pride, and attentiveness. Those with greater activity in the right anteriorfrontal region rated themselves higher on "withdrawal" traits such as irritableness, guilt, and fear. The rating scale is t he Positive and Negative Affect Scale (PANAS); whether approach (positive affect) or withdrawal (negative affect) traits are being rated is shown on the horizontal axis.

Participants who rated themselves higher on a series of positive affec-tive traits such as enthusiasm, pride, and attentiveness ("approach" traits) showed relatively greater EEG activity over the left anterior frontal region at rest, whereas those who rated themselves higher on negative affective traits such as irritableness, guilt, and fear {"withdrawal" traits) showed relatively greater EEG activity over the right anterior frontal region (Figure 4 ).

The idea that specific neural systems give rise to the enhanced attentional and perceptual processing of emotional stimuli is consistent with a psychological model suggested in the early years of the twentieth century (Wundt, 1907). This is the af-fective primacy hypothesis, which proposes that emotional stimuli are processed relatively automatically, making fewer demands on limited cognitive resources than do other types of stimuli.

The findings from the attentional blink study, as well as recent research demonstrating enhanced detection of emotional stimuli in the neg-lected field of patients with attentional neglect (Vuilleumier & Schwartz, 2001 pro-vide support for this early psychological theory

Although the amygdala appears to be involved in the facilitation of attention by emotion, it must interact with brain systems underlying attention and perception to accomplish this. Two mechanisms have been proposed to explain the amygdala's in-fluence on attentional and perceptual processes.

The first suggests that through learning the actual cortical representation of emotional stimuli is altered to allow for enhanced perception of emotional events (Weinberger, 1995). Evidence for this effect has been demonstrated with fear conditioning in rats by showing that the processing of neurons that have receptive fields for different tone frequencies is altered to en-hance perception of the frequency used as the conditioned fear stimulus. In humans, neuroimaging studies have reported enhanced auditory cortex activation for a tone used as a conditioned stimulus during fear conditioning (Morris et al., 2001a). In addition, words that have an emotional meaning elicit greater activation in the lin-gual gyms (A. K. Anderson, 2004), a region thought to be involved in the represen-tation of words (Booth et al., 2002). Although these neuroimaging studies in humans do not prove that emotion, via the amygdala, plays a causal role in creating lasting changes in the cortical representation of stimuli, they are consistent with the studies in rats observing this effect (Weinberger, 1995).

6.2 Facilitation of Attention and Perception "Finding the face in the crowd" is an example of a task in which performance is enhanced by emotion (Hansen & Hansen, 1988; Ohman et al., 20016). This is a visual search task in which participants must locate a target among distractors as quickly as possible. In this variation, the targets are either neutral faces or faces with emotional expressions, such as angry or happy.

When the target faces are angry, participants take less time to find the target than when the target faces are neutral or happy. Similar results have been observed for other negative stimuli, such as pictures of spiders and snakes among other natural stimuli (Ohman et al., 2001a). This is a "valence-asymmetric" effect: facilitation is apparent for negative stimuli, but not for positive ones.

1. The Connection Zajonc's research From this the investigator, Robert Zajonc, argued that affective ("affect" is a general term that includes emotions and preferences) judgments, such as how much you like a particular painting, occur

before, and independently of, cogni-tion.

6 Emotion , Attention and Perception Emotional events are distracting-despite your opinion, only moments before, about the drivers in front of you who slowed traffic to look at the accident, the car crash seized your attention, compelling you to pause and look before you returned your concentration to the road ahead. In some circumstances an emotional stimulus may

break through to awareness. You may be reasonably successful at tuning out the conversations around you at a party-until someone mentions an emotionally evoca-tive topic or word. Emotion can influence attention and perceptual processing by different means. Most of the studies that have examined the influence of emotion on attention or per-ception have reported effects for negative, arousing, or threat-related stimuli-often in combination. It is proposed that these stimuli, because of their potential impor-tance for survival, may receive priority in attention and perception (LeDoux, 1996; Ohman et al., 2001a; Whalen, 1998).

5.1 Arousal and Memory Hippocampal consolidation is a slow process by which memories become more or less stable over time. A series of studies has

demonstrated how the amyg-dala, through arousal, can influence hippocampal processing, modulating the con-solidation of hippocampal-dependent memories (McGaugh, 2000). By enhancing hippocampal consolidation with arousal, the amygdala alters the storage of new information in memory (McGaugh et al., 1992).

The other proposed mechanism for the facilitation of attention by emotion is a faster, more transient modulation of perceptual processing. There are connections to and from the amygdala and sensory cortical processing regions, such as the visual cortex (Amaral et al., 1992) (Figure 14). It is hypothesized that the amygdala, which receives input about the emotional significance of a stimulus early in process-ing, provides rapid feedback to sensory cortical areas of the brain, thus enhancing further perceptual and attentional processes. Consistent with this model, several neuroimaging studies have demonstrated enhanced activation in visual cortex for

emotional stimuli (e.g., Kosslyn et al., 1996; Morris et al., 1998). The strength of this activation response in the visual cortex is correlated with the strength of amyg-dala activation to these same stimuli (Morris et al., 1998). Researchers have at-tempted to determine whether the enhanced response in the amygdala for fear faces is causally related to the enhanced response in the visual cortex. Neuroimaging techniques demonstrated that damage to the amygdala eliminates the enhanced vi-sual cortex response normally observed for fear faces (Vuilleumier et al., 2004 ). By combining neuroimaging and studies of patients with brain damage, researchers have provided strong support for the conclusion that the amygdala's transient mod-ulation of visual processing regions underlies some of the effects of emotion on at-tention and perception. Through these two mechanisms-a lasting change in the cortical representation for stimuli linked to emotion and a transient enhancement of sensory cortical pro-cessing-the amygdala can alter the processing of incoming information to produce increased vigilance in the presence of threat (Whalen, 1998). Both these mechanisms highlight emotion's influence on perceptual regions, such as visual and auditory cor-tex, as opposed to other brain regions that are thought to underlie the allocation of attention (Corbetta & Shulman, 2002). A growing body of evidence suggests that many observed effects of attention are linked to enhanced perception (Carrasco, 2004) and enhanced processing in perceptual brain regions that occur with attention (Polonsky et al., 2000). Consistent with the notion that emotion enhances activation in visual processing regions, thus facilitating awareness and identification of emo-tional stimuli, a recent study found enhanced contrast sensitivity for stimuli cued with a fear face (Phelps et al., in press). Contrast sensitivity-the ability to detect subtle gradations of gray-is known to arise from the functioning of the primary vi-sual area (Carrasco, 2004). These results suggest that emotion can actually enhance how well we see. The studies showing that emotion can facilitate attention demonstrate that the line between attention and perception can be fuzzy. The facilitation of attention by emotion apparently is the result of mechanisms by which emotional stimuli receive priority in perception. Models of the neural mechanisms underlying emotion, atten-tion, and perception support this interpretation.

In an effort to determine the precise mechanism underlying the capture of atten-tion by emotion, researchers (Fox et al., 2001) employed the exogenous cueing tech-nique developed by Posner (1980). The

investigators suggested that emotion could capture attention by one of two mechanisms: it could either draw attention or hold attention. Participants were asked to respond as quickly as possible when a dot ap-peared either to the right or left of fixation and indicate by pressing a button on which side of the screen the dot appeared. The location of this dot probe was cued by a stimulus that was presented in the same location 150 milliseconds before the dot appeared. Most of the time, the cue predicted the correct location of the dot, but sometimes it predicted an incorrect location. As cues, the investigators used emo-tional and neutral words and faces to differentiate two components of attention (Figure 13 ).

6.1 Emotion and the Capture of Attention The researchers reasoned that if emotion can enhance the automatic orienting or shifting of attention to the cue location, then the participants should be faster for valid emotion cues than for valid neutral ones. This pattern of performance would support the interpretation that emotion draws attention. However, if emotion makes it difficult to withdraw or disengage attention from an inappropriate cue, then the participants should perform similarly for the valid emotion and neutral cues, but should respond more slowly for invalid emotional than for invalid neutral cues. In other words,

it should take the same amount of time for participants to shift atten-tion to both emotional and neutral cues, but longer to stop looking at an emotional cue and shift attention to another location in order to respond on the invalid cue tri-als. This pattern would be consistent with the idea that emotion holds attention and makes it difficult to disengage from an emotional stimulus. The findings supported the idea that emotion holds attention: the primary effect of the emotion cue was to make it more difficult to respond when the cue was invalid. These results suggest that the capture of attention by emotion makes it hard to disengage in order to fo-cus on nonemotional aspects of the task at hand.

6.2 Facilitation of Attention and Perception The face-in-the-crowd effect is thought to result from enhanced early processing of the emotional faces (Ohman et al., 2001a). Neuroimaging studies have suggested that the amygdala plays a role in this initial processing of emotional faces. Researchers have demonstrated that the amygdala shows robust activation to fearful, relative to neutral, facial expressions, and that this occurs even when the faces are presented so quickly that participants are unaware of their presentation (Whalen et al., 1998). In addition, a number of studies have found that

manipulating attention does not in-fluence the amygdala's response to "fear faces" (expressions of fear in others) (A. K. Anderson et al., 2003; Vuilleumier et al., 2002; Williams et al., 2004). In most cases, the amygdala shows a similar response to fear expressions whether or not they are consciously detected or the focus of attention (see the accompanying Debate box for a further discussion of this topic). These results are consistent with the idea that the emotional content of faces is processed before attention is deployed.

4.4 Mere Exposure All the types of emotional learning described thus far rely on linking a stimulus or action to something that is "good" or "bad." When a preference or attitude is ac-quired through mere exposure, no linkage is required; just the simple repetition of a stimulus can make it likable. The mere exposure effect is based on familiarity, and so only the (repeated) presentation of the stimulus is necessary. In a typical mere expo-sure study,

participants are shown neutral stimuli, such as abstract patterns. Some patterns are presented perhaps 10 times, others 5 times or once, and some patterns are not shown at all. After the exposure procedure, participants are asked to rate how much they like these abstract patterns. They are more likely to give high ratings to the patterns that they have been exposed to more frequently than to those they have been exposed to less frequently or not at all.

5.1 Arousal and Memory If arousal, via the amygdala, modulates the storage of declarative memories, there should be different forgetting curves for arousing and nonarousing stimuli. This has been demonstrated in a number of studies. In an early experiment, participants were presented with

participants were presented with word-digit pairs (Kleinsmith & Kaplan, 1963). Half the words were emotional and arousing, half were neutral. Participants were then presented with the word alone and asked to recall the paired digit. Some participants were given this memory task immediately after encoding, others a day later. Participants who were asked to recall the digits immediately showed somewhat better memory for the digits paired with neutral words, although this difference was not significant. Partic-ipants who were tested 24 hours later showed significantly better memory for the digits paired with high-arousal words. Comparing across the groups, there was evi-dence of forgetting over time for the neutral word-digit pairs, whereas memory for the arousing word-digit pairs did not diminish over time (Figure 10). Consistent with the idea that the amygdala enhances consolidation or storage processes, patients with damage to the amygdala show similar patterns of forgetting for arousing and neutral words (LaBar & Phelps, 1998).

4.1 Classical Conditioning The ability to acquire and report this explicit represen-tation depends on medial temporal structures, the so-called hippocampal com-plex, that are close to the amygdala. Patients with damage to the hippocampus, who have an intact amygdala, show the opposite pattern of results;

show normal autonomic conditioning, as measured by SCR, but they are unable to report that the blue square predicts the shock (Bechara et al., 1995).

5.1 Arousal and Memory It is a well-documented finding that there is better declarative memory for arousing, emotional stimuli. How does this happen? To understand how this works, we can look at the neural mechanism underlying the influence of emotional arousal on memory. A number of studies have shown

shown that the amygdala, which is critical for the ac-quisition and expression of aversive conditioning, also has a secondary role in mem-ory. Patients with damage to the amygdala do not show arousal-enhanced memory (Cahill et al., 1995; LaBar & Phelps, 1998). Neuroimaging studies reveal a correla-tion between the strength of the amygdala response to an emotional stimulus at encoding and the likelihood of successful recollection of that stimulus at a later time (Cahill et al., 1996; Hamman et al., 1999). These results suggest the amygdala can influence declarative memory for emotional events. But it is neighboring medial temporal lobe structures, in and around the hippocampus, that underlie the acquisi-tion of declarative memory: the amygdala has its influence by interacting with the hippocampus.

6.2 Facilitation of Attention and Perception In addition, a series of studies has demonstrated that the time needed to detect negative stimuli is not influenced by factors such as the number of distractor items (Ohman et al., 2001a, 20016). These results are reminiscent of other findings on attentional search tasks in which certain visual features "pop out" so that identify-ing these target stimuli among distractor items is relatively easy and does not require that each stimulus in the display be examined. It has been suggested that

visual fea-tures that pop out during search tasks are more elementary and may be processed more easily without attention (Treisman & Souther, 1985). On this basis, it is pro-posed that negative faces (and other natural emotional stimuli) receive priority in processing and their enhanced detection on the visual search task is due to a mecha-nism that operates without requiring attention (Ohman et al., 2001a).

4.3 Instructional and Observational Learning Both classical and instrumental conditioning depend on emotional experience for learning to occur-

you must receive a stimulus that you perceive as positive-rewarding or negative-punishing.

2. Defining Emotion But how can we define emotion in a way that captures the range of emotional expe-rience, yet is objective and therefore can allow scientific investigation? Researchers and philosophers have struggled with this problem

Researchers and philosophers have struggled with this problem. Although most people have little difficulty describing their individual emotions, a single definition of emotion is elusive (Russell, 2003). Thus the term emotion has been used to refer to mental and physical processes that include aspects of subjective experience, evaluation and appraisal, motivation, and bodily responses such as arousal and facial expression. For the purposes of this chapter (adapted from Scherer, 2000), we will use the term emotion when referring to a relatively brief episode of synchronized responses (which can include bodily responses, facial expression, and subjective evaluation) that indi-cate the evaluation of an internal or external event as significant. Emotion refers to the range of reactions to events that are limited in time, such as experiencing joy, fear, or sadness in response to hearing some news.

A closer look results and discussion

Results In both the fMRI and patient studies, normal control participants exhibited a physiological response con-sistent with fear in reaction to the presentation of the Threat (relative to Safe) stimulus. In autonomic mea-sures taken during the fMRI study, the participants showed increased SCR to Threat versus Safe. In the patient study, the normal control participants showed a potentiated startle reflex response to Threat ver-sus Safe. These results suggest that simply instructing someone about the potential aversive properties of a stimulus can elicit a fear response. Both the fMRI and patient studies also found that the left amygdala is important for this expression of instructed fear. In the fMRI study, activation of the left amygdala was ob-served in response to the Threat versus Safe stimulus, and the magnitude of this activation was correlated with the magnitude of the SCR response. In the patient study, patients whose damage included the left amygdala failed to show potentiated startle to the Threat stimulus. Discussion These results suggest that the left amygdala responds to verbally instructed fears and plays a critical role in their expression. The left amygdala may be particularly important because these fears require linguistic interpretation, which is known to rely on the left hemisphere in most people. Animal models of the neural mechanisms of fear learning have relied on fear conditioning, in which learning occurs through direct aver-sive experience. These results suggest that similar neural mechanisms may underlie fears that are uniquely human-that is, fears that are linguistically communicated and are imagined but never actually experienced.

One of the interesting distinctions between SCR and potentiated startle measures is

SCR reflects arousal that can occur in response to both negative and positive stimuli, whereas the startle reflex is modulated by valence-that is, it increases when the participant is in a negative emotional state and decreases when the participant is in a positive emotional state. Both measures provide an indirect, physiological assess-ment of an emotion, but they differ in the type of emotional information they register.

5.3 Mood and Memory Mood induction-the deliberate attempt to change a participant's mood-is used to assess the mood-congruent memory effect. In a typical study, participants are

first asked to fill in a mood questionnaire that asks them to rate how happy, sad, positive, or negative they are feeling at that moment. A mood-induction procedure follows: for example, participants may be shown a movie and told to try to feel whatever mood the movie seems designed to elicit. A second questionnaire is ad-ministered to determine whether mood induction was successful. Following success-ful mood induction, participants are given stimuli to remember, such as positive words (for example, humor), neutral words (for example, cloth), or negative words (for example, failure). Memory for the words is then assessed, typically by free recall (i.e., participants are not given specific cues but simply instructed to recollect as many of the words as possible). The mood questionnaire is administered a third time, to ensure that the induced mood was in place at the time of test. If in fact it was, participants will show better recall for words whose valence is congruent with the mood state (for instance, they will remember more positive words when in a pos-itive mood) than words whose valence is incongruent with the mood state (for in-stance, they will remember fewer negative words when in a positive mood).

3.1 Manipulation by Mood Induction As mentioned earlier, mood is a more stable and diffuse affective state than emotion, longer lasting and not necessarily linked to a specific event or object. In research, one method that has been used to manipulate affective experience is to change the par-ticipant's mood. This technique, called mood induction

focuses on changing the baseline state reported by the participants on arriving at the laboratory. Typical means of changing a participant's mood are to show the participant affective film clips (hilariously funny or grim and despairing, depending on the change sought by the experimenter), to play music (again, upbeat or solemn), or to ask the participant to focus on affective situations, real or imagined, that result in either positive or negative mood states. Mood induction is considered successful if the participant reports a shift of mood in the predicted direction.

2.2.2 The Approach - Withdrawal Distinction Emotions may be classified along the dimension of motivation, which can be conceptualized as the propensity to action that is a component of some emotional responses. Different emotions lead to different goals for action. Some, such as

hap-piness, surprise, and anger, are referred to as "approach emotions" in that they evoke the desire to approach the stimulus object or situation. In contrast, others, sadness, disgust, and fear, are referred to as "withdrawal emotions" in that they evoke the desire to withdraw from objects or situations linked to these emotions.

2.2.1 Circumplex model What does the circumplex model of emotion puts

"arousal" on one axis and "valence" on the other (Barrett & Russell, 1999; Russell, 1980). "Arousal" refers to both the strength of the response to a stimulus and to activation, that is, the mobilization of resources. "Valence" (or "evaluation") reflects the degree to which the experience is pleasant or unpleasant. Using these two dimensions of emotional experience, the cir-cumplex model creates a graphic framework in which a range of emotional states can be positioned

3.4 Measuring Emotion Indirectly Second way of indirect assessment of emotion

A second indirect measure of emotional assessment is the inhibition or facilitation of a behavior, such as response time or eye movements. The pleasure of seeing a joyful reunion between friends in the yard outside your classroom may cause you to linger your gaze and be slow to respond to a question. Emotion can influence our actions and the ease with which we respond by both in-hibiting and facilitating behaviors.

4. Emotional Learning Acquiring Evaulations Why do you like some movie genres and not others? Some brands of soap and not others? Some kinds of people and not others? In this discussion, the supposedly rational answer-in the case of movies, "because I enjoy the special effects"-does not suffice. What underlies these preferences? Here's another instance: have you ever felt uneasy, for no good reason, around someone you barely knew-and then real-ized that the person reminded you of someone who had once done you harm? What underlies this emotional reaction?

All these instances involve emotional learning-learning, one way or another (and not always on the basis of fact), that people, places, and things are not all neu-tral but often acquire some kind of value. Some people, places, or things are better or worse, comforting or scary, or simply good or bad. This value determines, in part, our emotional reaction to the person, place, or thing.

2.2.2. The Approach - Withdrawal Distinction This asymmetry also reflects emotional responses. In an intriguing study with infants, researchers found that infants with more dominant right-hemisphere EEG activity at rest were more likely to cry and fuss when separated from their moth-ers in comparison to infants with more dominant left-hemisphere EEG activity (Davidson et al., 2000).

Although all healthy people are capable of both approach and withdrawal dispositions and emotional responses, the relative frequency and intensity of these emotional reactions in a given person may be related to the rel-ative baseline asymmetry in the activity of the anterior right and left cerebral hemispheres.

4.4 Mere Exposure Mere exposure effects have been observed with a range of stimuli, including Chinese ideographs, musical tunes, and nonsense syllables (Zajonc, 1980).

Although the mere exposure effect results from familiarity, it does not require recollection of previous experience with the stimulus. A study examining preferences for novel musical tunes found that the mere exposure effect was equally strong for tunes the participant could and could not identify as having been previously pre-sented (Wilson, 1979). Similar effects have been observed for other types of stimuli. The factor that predicted the formation of a preference for the tunes and other stim-uli was the amount of previous exposure, not awareness of that exposure (Zajonc, 1980). The notion that mere exposure effects can be obtained independent of aware-ness receives further support from studies demonstrating the mere exposure effect for stimuli presented subliminally (Bornstein, 1992). The next time you find yourself humming along with a song on the radio, remember: the more you hear it, the more you'll probably like it.

5.4 Memory for Emotional Public Events There is only so much that can be done to manipulate emotion in a controlled and ethically responsible fashion. Because emotional reactions studied in the labora-tory are therefore mild and constrained, some researchers have chosen to study emotion and memory in "natural experiments."

An area that has been investi-gated in this way for its psychological, historical, and cultural importance is memory for emotional public events. Although these studies cannot be nearly as controlled or detailed as laboratory research, they nevertheless provide a window through which we can have another view of the link between human memory and emotion.

2.2.1 Circumplex Model What is arousal?

Arousal is the overall term for the bodily changes that occur in emotion, such as changes in heart rate, sweating, and the release of stress hormones in response to a stimulus-the changes in your physical self when you're watching a horror movie or asking for a date. The intensity of the emotional reaction may be assessed by the strength of these responses.

2.2.1 Circumplex Model What is valence?

Arousal is the overall term for the bodily changes that occur in emotion, such as changes in heart rate, sweating, and the release of stress hormones in response to a stimulus-the changes in your physical self when you're watching a horror movie or asking for a date. The intensity of the emotional reaction may be assessed by the strength of these responses. Dictonary: Valence, as used in psychology, especially in discussing emotions, means the intrinsic attractiveness (positive valence) or aversiveness (negative valence) of an event, object, or situation.[1] However, the term is also used to characterize and categorize specific emotions. For example, the emotions popularly referred to as "negative", such as anger and fear, have "negative valence". Joy has "positive valence". Positively valenced emotions are evoked by positively valenced events, objects, or situations

4.1 Classical Conditioning Emotional classical conditioning can be expressed in different ways

As autonomic conditioning, it can be expressed through bodily responses, such as an arousal response. As evaluative conditioning, it can be expressed through a prefer-ence or attitude: a stimulus that predicts a negative emotional event may be rated more negatively. Most studies of emotional classical conditioning examine either au-tonomic responses or subjective reports of evaluation, although these two types of conditioned responses are often acquired simultaneously.

2.2 Dimensional Approaches

Dimensional approaches to the exploration of emotion seek to classify the range of emotional states on certain specific scales. Our emotions are not "on" or " off," but are experienced on a continuum. The two primary dimensional approaches used by researchers emphasize, and attempt to measure, different aspects of emo-tional experience.

A closer look introduction

Do symbolically communicated and imaginary fears rely on the same neural mechanisms as fears acquired through direct, aversive experience, as in fear conditioning? This question was addressed in two studies (Funayama et al., 2001; Phelps et al., 2001 ). Both groups of investigators were interested in how verbally communicated fears are represented in the brain and whether expressing this type of emotional learning depends on the amygdala, which has been shown to be critical in fear conditioning.

3.4 Measuring Emotions Indirectly Third way is psychopsychical Two important psychophysiological responses assessed by researchers interested in emotion are the skin conductance response and the potentiated eyeblink startle. The skin conductance response (SCR) is an

Even a subtle emotional stimulus can produce a response from the sweat glands (controlled by the autonomic nervous system). The increased sweating creates a change in the electrical conductivity of the skin. The SCR is assessed by placing elec-trodes on the participant's fingers; the electrodes pass a small electrical current through the skin. Changes in resistance to the current, which occur with subtle changes in the sweating, are measured. You may already be familiar with the SCR be-cause it is typically used as a component of the lie detector. Because it is often assumed that there is an emotional reaction related to guilt or anxiety when telling a lie, an-swers to questions that are known to be true (for example, your name or address) should yield less of an SCR than answers that are not true.

4.1 Classical Conditioning Even though autonomic and evaluative conditioning can occur simultaneously, there is some evidence that these two types of emotional classical conditioning can be dissociated. This evidence comes from studies of extinction

Extinction is the de-crease in a learned emotional response that occurs when a stimulus is presented enough times without the occurrence of the emotional event that the participant learns that this conditioned neutral stimulus no longer predicts the occurrence of the emotional event. Your unfortunate car accident again: the first time after the acci-dent you drive through the intersection where it occurred, you may feel nervous-this is a conditioned autonomic response to that particular location. Several months later, however, after you have driven through this intersection a number of times with no further mishap, your nervousness may fade; it has been extinguished. This is an example of the extinction of a conditioned autonomic response.

4.1 Classical Conditioning In the study of emotion, it has become clear that stimuli that are linked with pos-itive or negative events themselves take on affective qualities and elicit affective reac-tions. For example,

For example, if you have been in a car accident, it would not be surprising if you were to feel uneasy the next time you found yourself at the intersection where the accident happened. The association between the previously neutral location and the negative accident results in a conditioned arousal response and a feeling of nervous-ness linked to that location. It is not uncommon for us to feel anxious or aroused around people, places, or things that have previously been connected with unpleasant experiences. This is the result of emotional classical conditioning, the learned associ-ation between a neutral event and an emotional event.

4.3 Instructional and Observational Learning There are other means of emotional learning that do not require direct emotional experience, but depend instead on instruction or observation. Why, for instance, are some people afraid of germs and why do most people try to avoid them? Outside a research facility or academic setting-and for English majors not even then-most people have never seen a germ. And as far as our unassisted perceptual systems are concerned, germs are an imaginary concept.

However, we have been told about the negative value of germs (and admonished from childhood, and in signs in restrooms, to wash our hands to avoid them). This is an example of instructional learning. (If the instruction is threatening enough, and not modulated by experience, the healthy avoidance of germs can become an unhealthy phobia.)

3.4 Measuring Emotion Indirectly Third way is psychophsyical The strength of the startle reflex, the response that follows a sudden and surpris-ing stimulus such as a sudden loud noise, can be measured.

If you are walking down a relatively quiet street at midday and suddenly hear a car backfire, you might be star-tled. If you hear the same sound late at night on a deserted street when you're already feeling a little anxious, you might startle even more. Startle is a reflex that is potentiated, or enhanced, when we are in a negative emotional state. The degree of po-tentiation can be measured in the laboratory by examining the strength of the eyeblink response, a component of the startle reflex. The strength of this response is measured by electrodes placed on the skin over the eye muscles. The amount of muscle contrac-tion reflects the strength of the startle reflex. We blink harder when startled more, which is called a potentiated eyeblink startle A researcher interested in a participant's emotional responses to different scenes might present the scenes one at a time and un-expectedly present a loud click or popping noise. The difference in the strength of the potentiated eyeblink startle to the sound provides information about the emotional state evoked by the different scenes. Scenes that are more negative elicit a stronger star-tle reflex response than scenes that are neutral or more positive (Lang et al., 1990).

2. Defining Emotion

In an effort to establish a scientific framework for the investigation of emotion, researchers have focused on various aspects of affective experience (facial expres-sions, feelings of arousal, motivation), attempting to capture a range of emotion re-sponses such as sadness, fear, and happiness. The two main current approaches classifying the range of emotional states are the attempt to define basic emotions and the attempt to explore their dimensions. Each approach is more or less useful, de-pending on the question being asked.

5.1 Arousal and Memory To demonstrate that the amygdala modulates storage, investigators have dis-rupted or enhanced amygdala processing in rats after memory encoding.

In one study rats were given a maze-learning task, which depends on the hippocampus for normal learning. Immediately after learning, some of the rats were given a pharma-cological agent that induced an excitation response in the amygdala; the other rats were given a (nonactive} saline injection. Those rats whose amygdalas were artifi-cially excited after learning showed better memory for the maze than the rats that re-ceived saline (Packard & Teather, 1998). The mechanism by which the amygdala modulates consolidation relies on activation of the {3-adrenergic system in the amyg-dala. Beta-blockers ( drugs that block the action of the 13-adrenergic system by block-ing 13-adrenergic receptors) also block the effect of arousal on declarative memory (Cahill et al., 1994; McGaugh et al., 1992). It has been suggested that one of the adaptive functions of having a long consolidation process for the storage of declara-tive memories is to allow time for the arousal response to enhance the retention of events linked to emotional consequences.

4.2 Instrumenting Conditioning: Learning by Reward or Punishment

Instrumental conditioning requires action that can be reinforced. It is this ac-tion, and the stimulus prompting it, that acquires affective value. However, along with the action and stimulus, the affective value of a range of other, associated stim-uli may be altered as well. An addict learns to associate taking the drug with reward. Drug taking is also linked to a number of other stimuli: the location where it usually takes place, the paraphernalia used, other people who use the drug with the addict, the dealer who sells the drug. All these stimuli, simply by their association with the action of drug taking, can acquire affective value by classical conditioning. Instru-mental and classical conditioning can go hand in hand in an intimate relationship that makes changing behaviors such as taking drugs so challenging.

Comprehension check 1. In what sense is the relationship between emotion and cognition a very old ques-tion? In what sense is it new?

It is a old question because the relationship between emotion and cognition seem questioned a lot by philiosphers and seem that they areboth distinct e.g Plato believed humans had three "soul" : intellect, will and emotions This laid groudwork over centuries about cognition and its relation to emotion In modern times, it is still quite a fresh debate as debating back to the influence of computers (ignoring the role of emotion) and also neuromagining techniques showing some brain structures are specialised for processing emotional stimuli

5.4 Memory for Emotional Public Events One of the first emotional public events studied by psychologists was the assassi-nation of John F. Kennedy in 1963. This event shocked the nation, and reactions to it were highly emotional. Two psychologists, Roger Brown and James Kulik (1977), studied the qualitative aspects of memory for this event, asking people to recall inci-dental details of their experience of the event, such as where they were and whom they were with when they heard about it.

Many respondents had detailed recollec-tions and believed their memory to be extremely accurate, almost like a photograph that recorded every aspect of the scene. Brown and Kulik introduced the term flashbulb memory to describe memory for surprising and consequential events; the phrase reflects the vivid and detailed nature of the recollections reported. Brown and Kulik suggested that there are special mechanisms for the formation of memories for highly charged events and that they elicit a "print now" response from the memory system, which ensures that the memory remains accurate and not forgotten.

4.2 Instrumenting Conditioning: Learning by Reward or Punishment Neuroimaging studies have consistently shown activation of the stria tum in response to a reward the participant perceives as such (e.g., Delgado et al., 2000; Knutson et al., 2001), and drugs that block the action of dopamine have been shown to lead to impairments in performance of rewarded learning tasks (Stellar & Stellar, 1984).

One of the most interesting findings to emerge from research on the neural basis of reward learning is that the neural system involved responds to all types of reward, whether it is a drug given to an addict (Breiter et al.,1997), a primary rein-forcer such as food (Rolls et al., 1980), or a secondary reinforcer such as money (Delgado et al., 2000; Knutson et al., 2001). The fact that a common neural path-way mediates both primary and secondary reinforcers suggests that this system is important for coding perceived reward value. However, what is rewarding to one person may not be rewarding to another-and may be neither healthy, necessary, nor inherently valuable.

3.4 Measuring Emotion Indirectly Third way of indirect assessment of emotion A third technique of indirect assessment makes use of psychophysiology, the study of the relationship between mental states and physiological responses What is autonomic, sympathetic, parasympathetic nervous systems?

One of the primary ways that emotion differs from other mental processes is that emotion typically results in substantial changes in our physical state. The auto-nomic nervous system, part of the peripheral nervous system, is concerned with maintaining the body's internal environment. Its sympathetic branch, which pre-pares the body for action in the face of, say, a threatening event, may become more activated and initiate a number of physiological responses, including pupil dilation, sweating, and increased heart rate and blood pressure. Correspondingly, the parasympathetic branch is dominant when the threat is past, and the body is at rest; its functions, which essentially conserve energy, such as by slowing heart rate, can also be measured (Figure 6). An underlying emotion may also be reflected in reflex responses and facial muscle movements. All these bodily responses can be asessed with psychophysiology.

4. Emotional Learning Acquiring Evaulation Secondary reinforcers

Other stimuli are motivating only because we have learned that they represent positive or negative consequences. A bathtub full of hundred-dollar bills will not keep you warm (or at least not very warm), taste good, or provide safety-nonetheless, a bath-tub full of hundred-dollar bills would be very nice to have. Money has value because we have learned to associate it with stimuli that are inherently motivating: with money we can buy things that keep us warm, taste good, and provide safety. Money is a classic example of a secondary reinforcer, a stimulus whose motivational prop-erties are acquired through learning

4. Emotional Learning Acquiring Evaulation Primary reinforcers

Some emotionally evocative stimuli are inherently positive or negative; there is no need to learn their value. A mild shock is aversive to all animals, from family pets to Nobel laureates. These types of stimuli are called primary reinforcers because their motivational properties occur naturally and do not need to be learned. Primary reinforcers are reinforcers that have innate reinforcing qualities. These kinds of reinforcers are not learned. Water, food, sleep, shelter, sex, and touch, among others, are primary reinforcers. Pleasure is also a primary reinforcer.

1. The Connection The other position, championed by Richard Lazarus (1981, 1984), held that emotion could not occur without cognitive.appraisal Example horror movie

Sweating and an increased heart rate, both signs of arousal, may occur when you watch a horror movie, talk to some-one you find attractive, or work out at the gym; but in each case your appraisal of your emotional response would very likely be different. Thus, your emotional response-disgust, say, or joy-depends on the reason you experience arousal, and this determi-nation is part of cognition (Schacter & Singer, 1962).

4.1 Classicial Conditioning One of the more widely studied forms of autonomic conditioning is aversive, or fear conditioning. Fear conditioning occurs when a neutral stimulus paired with an aversive or fearful event comes to elicit a fear response when the stimulus is presented alone.

That is what is happening when the acquired arousal response is made to the site of the car accident. The experience is a familiar one: most of us could find examples in our lives to substitute for "car accident" and "intersection." Learning by aversive con-ditioning has been considered a model for fear learning in general, and it has been sug-gested that it may be specifically related to phobias (Ohman & Mineka, 2001).

5.3 Mood and Memory Mood-congruent memory effects can be observed when memory encoding occurs before or after mood induction. Therefore, the mood-congruent memory effect is the result of altering the retrieval, rather than the encoding or storage stage of memory. Two hypotheses have been proposed to explain the influence of mood on memory retrieval.

The first suggests that mood creates a bias in responding: the memory representations for the mood-congruent and mood-incongruent stimuli are equally accessible, but participants are biased to respond to the mood-congruent stimuli (Schwarz & Clore, 1988). The second hypothesis suggests that mood actu-ally changes the accessibility of the memory representation during retrieval, so that a given mood leads to greater activation of memories for stimuli whose valence is consistent with that mood. For this reason, memories of mood-consistent stimuli are more easily retrieved (Bower, 1981). With most memory tests using free recall, it is difficult to distinguish a tendency or bias to respond with mood-congruent stimuli from a change in the accessibility of these stimuli to retrieval. However, in a clever study using a modified recognition memory test, investigators were able to demon-strate that the primary mechanism by which mood alters memory is the greater accessibility of mood-congruent memories (Fiddler et al., 2001 ). In other words, mood can actually determine which memories are most available for explicit re-trieval at any given time.

5.2 Stress and Memory The effect of arousal on memory storage can help to explain why those events that are most exciting, embarrassing, or nerve wracking may receive preferential treatment in memory. However, prolonged stress and extreme arousal can have the opposite effect, impairing memory performance. The effect of arousal and stress on declarative mem-ory can be characterized by an inverted U-shaped curve (Figure 11). Mild to moderate arousal enhances memory performance, but if the arousal response is pro-longed or extreme, memory performance suffers.

The mechanism underlying this stress-induced memory impairment is related to hormonal changes that occur with long-term stress. Glucocorticoids, a group of stress hormones released by the adrenal gland, are the primary culprit. In studies with rats, researchers have shown that extended exposure to stress leads to increased levels of glucorticoids that can reduce the firing rate of hippocampal neurons, impair memory performance, and, if exposure is long enough, lead to hippocampal atrophy (McEwen & Sapolsky, 1995). The hippocampus has two types of glucocorticoid receptors, which are affected by different levels of glucocorticoid exposure. The exis-tence of these two types of receptors may help to explain why different levels of expo-sure to arousal and stress hormones lead to either an enhancement or an impairment of memory.

2.2.1 Circumplex model Example For example, "sadness," "fear," "excitation," and "nervousness" are considered discrete emotional states. These could be understood as

These could be understood as varying along the dimensions of arousal and valence. "Sadness" and "fear" are both unpleasant, but "sadness" is not as arousing or activating as "fear." "Excitation" and "nervous-ness" are both arousing states, but "excitation" is relatively positive and "nervous-ness" is relatively negative. As more emotional responses are plotted, the reason for the name of the model becomes clear: the data fall in a circular pattern (Figure 3 )

A closer Look Summary

Two related studies that investigated, in different populations, the neural mechanisms underlying imagi-nary fears are considered together; both were published in 2001. Elizabeth A. Phelps, Kevin j. O'Connor, j. Christopher Gatenby, john C. Gores, Christian Grillon, and Michael Davis reported their results in a paper titled "Activation of the Left Amygdala to a Cognitive Representation of Fear," Nature Neuroscience, 4, 437-441; E. Sumie Funayama, Christian Grillon, Michael Davis, and Elizabeth A. Phelps reported theirs in "A Double Dissociation in the Affective Modulation of Startle in Humans: Effects of Unilateral Temporal Lobectomy," Journal of Cognitive Neuroscience, 13, 721-729.

A closer look method

Two techniques were used to assess human brain function: functional magnetic resonance imaging (fMRI) in normal participants (Phelps et al., 2001) and physiological responses of patients with amygdala lesions (Funayama et al., 2001 ). In each of the studies, participants were told that the presentation of a colored (for example, blue) square would indicate the possibility that a mild shock to the wrist would be delivered: this was called the "Threat" stimulus. Participants were also shown a square of another color (for exam-ple, yellow) and were told that this stimulus indicated that no shock would be delivered: this was called the "Safe" stimulus. In the fMRI study, normal participants were presented with the Threat and Safe stimuli while responses in the amygdala were assessed. Skin conductance responses were also measured to ob-tain a physiological indication of a fear response. In the patient study, normal controls as well as patients with left, right, and bilateral amygdala damage participated in an experiment of similar design in which eye-blink startle to the Threat and Safe stimuli was assessed as a measure of fear learning. In both the fMRI and patient study, none of the participants actually received a shock to the wrist.

3.2 Manipulation by Evocative Stimuli The most common laboratory technique used to manipulate emotion (as opposed to mood) is the presentation of emotionally evocative stimuli.

Typical stimuli used to elicit emotional responses in participants are pictures of faces with different emo-tional expressions; pictures of emotional scenes such as an appealing baby or the very unappealing muzzle of a revolver (Figure 5); words that vary in valence and arousal; money; loud noise; and mild shock. By presenting participants with stimuli that evoke emotional experiences, investigators can explore the impact this emo-tional experience has on mental and physical behaviors and neural responses.

4.3 Instructional and Observational Learning

Unlike other species, we can learn about the emotional significance of events and stimuli through symbolic means such as language. We do not have to experience directly negative or positive consequences to know whether a stimulus is good or bad. Learning through instruction is a common means of emotional learning in humans, and it is highly effective. Learning emotional responses to neutral stimuli that are directly linked to aversive consequences (conditioning) is similar to learning through verbal communication (instruction) (Hugdahl & Ohman, 1977).

5.4 Memory for Public Events One of the first studies to demonstrate significant errors and distortions in memories for emotional public events examined memory for the Challenger explo-sion in 1986 (Neisser et al., 1992). Within a few days of the event, students were asked to recollect what they knew and how they heard about it. Three years later, they were again asked to recall this event.

When comparing the early and later rec-ollections, the investigators found significant differences between them. For exam-ple, a few days after the explosion, most respondents reported hearing the news from someone before seeing the television reports. After a few years, however, most re-spondents stated that they had been watching the Challenger flight on television and saw the explosion as it occurred. But despite the distortions of most of the second reports, all respondents were extremely confident in the accuracy of their memories. Similar results have recently been reported for memories of the 9/11 terrorist attack (Talaricho & Rubin, 2003). It seemed as if the powerful nature of these events over-rode any doubt.

4.1 Classical Conditioning - Summary

With autonomic conditioning procedures, extinction typically is rapid. After a few extinction trials in which the neutral event occurs without the aversive one, the conditioned autonomic response may no longer be expressed (e.g., LaBar et al., 1995; Ohman & Soares, 1998). Evaluative conditioning, on the other hand, is very hard to extinguish. Once a preference or attitude is acquired, this preference does not seem to diminish, even when there are twice as many presentations of the pre-viously neutral stimulus without the occurrence of the emotional event and the participant is fully aware that the presentation of this stimulus no longer predicts the emotional event (De Houwer et al., 2001). Even if you extinguish your auto-nomic response when you pass the intersection where you had the accident, it is likely you will still dislike this intersection. This resistance to extinction for evalu-ative conditioning differentiates conditioned preferences from other types of clas-sical conditioning.

Comprehension Check: 2. What is the key difference between Lazaru's and Zajonc's positions?

Zajonc proposed that the affective judgements occur independently of cognition However, Lazaru's argued that emotion could not occur without cognitive apparaisal The emotional response (e.g joy) depends on the reason you experience arousal, and this determination is part of cognition.

1. The connection What did Zajonc argue after Lazarus say emotion could not occur without cognitive apprasial?

Zajonc, then, argued that emotion can occur independently of cognition, and Lazarus believed that emotion de-pended on a subset of cognitive processes; their writings helped to draw researchers' attention to the interaction between emotion and cognition.

2.1 Basic Emotions "On the Origin of Species" (1859), Charles Darwin was one of the first to propose that

a limited number of basic and universal hu-man emotions. He derived this idea in part from colleagues who had studied differ-ent cultures around the world. When Darwin asked them about the emotional lives of people far removed from Western culture, they all reported similar emotional facial expressions. Darwin suggested that this universality of emotional expression implies a common emotional experience.

4.1 Classicial Conditoning Aversive conditioning has been studied extensively in both humans and nonhu-mans. Across species, it has been shown that the amygdala is a critical brain struc-ture in both the acquisition and expression of aversive conditioning (LeDoux, 1996). Humans with damage to the amygdala do not

acquire conditioned fear responses (Bechara et al., 1995; LaBar et al., 1995), but they show a normal ability to report that the neutral stimulus predicts the aversive or fearful event. For example, a patient known as S.P., who had sustained bilateral damage to the amygdala, and normal control participants were given several pairings of a blue square and a mild shock to the wrist (Figure 7). After a few trials, the normal participants showed a skin con-ductance response to the blue square presented alone, indicating autonomic condi-tioning. S.P., however, showed no evidence of arousal to the blue square alone, even though her arousal response to the shock was normal. When S.P. was shown her own data and asked what she thought about the results, she answered: I knew that there was an anticipation that the blue square, at some particular point in time, would bring on one of the volt shocks. But even though I knew that, and I knew that from the very beginning, except for the very first one where I was surprised, that was my response. I knew it was going to happen. I expected that it was going to hap-pen. So I learned from the very beginning that it was going to happen: blue and shock. And it happened. I turned out to be right, it happened! (Phelps, 2002) It is clear that S.P. understood fear conditioning and had episodic memory of the events of the study.

3. Manipulating and Measuring Emotion As social animals, we often try to manipulate and measure the emotions, moods, and attitudes of those around us-that is what we are doing when we try to comfort a grieving friend or reassure a frightened child. But although manipulating and mea-suring affect is a part of human experience, it is a challenge to do so in a manner that

assessed objectively and reliably. Researchers interested in emotion have met the challenge by using a number of techniques.

4.1 Classical Conditioning t is likely that both types of emotional classical conditioning-autonomic con-ditioning and evaluative conditioning-occur simultaneously. For instance,

aversive conditioning study might pair an abstract pattern with a mild electric shock. After several presentations of such pairings the abstract pattern may come to elicit an arousal response when presented alone. This is an indication of autonomic con-ditioning. At the same time, if participants are asked to rate how much they like the abstract pattern compared to a similar pattern that was never paired with shock, they might rate the pattern paired with shock more negatively, thus indicating eval-uative conditioning.

2.1 Basic emotions Paul Ekman Each of these expressions is characterized by a unique subset of facial muscle movements, and the ability to convey them appears to be in-nate. Infants display these facial expressions, as do people who have been blind since birth and so never had the opportunity to mirror them. These facial expressions ap-pear to be

be universal and similar in range, appearance, and interpretation whether you are from Papua, New Guinea, or Buffalo, New York.

1. The Connection The idea, no longer tenable (justifiable), that emotion and cognition are distinct and separa-ble mental activities can be traced back to early philosophical thought. Plato, for ex-ample,

believed that human beings have three "souls," corresponding to three aspects of human nature: the intellect, the will, and the emotions. The influence of this early philosophical thought laid the groundwork for debates over the centuries about cognition and its relation to emotion.

2.1 Basic emotions Using these social, emotional facial expressions as stimuli in experiments, re-searchers have started to study the neural systems underlying the perception of basic emotional expressions. It has been shown that

certain neural systems seem to be spe-cialized for the perception of specific emotional expressions For example, there are many reports of patients with bilateral damage to the amygdala who have a specific deficit in the perception of expressions of fear (Adolphs et al., 1999) other neural structures-the insula and basal ganglia-have been shown to underlie the perception of disgust (Calder et al., 2001), and a neurotransmitter system (acti-vated by dopamine) and a neural structure (the ventral striatum) are important for the perception of expressions of anger (Calder et al., 2003; Lawrence et al., 2002). Although there is not yet a complete understanding of the specific neural represen-tations that underlie the perception of each of the six basic emotion expressions de-fined by Ekman, this research supports the idea that there are in fact distinct basic emotions, emotional reactions that are universal across cultures. However, it is im-portant to acknowledge that Ekman's six basic emotions do not capture the range of human emotional experience. Several more complex emotions, among them guilt and love, are less clearly linked to specific facial displays.

2.1 Basic emotions Nearly a hundred years later Paul Ekman and his colleagues studied the facial expression of emotion and suggested that there (after Darwin)

corresponding to anger, disgust, fear, happiness, sadness, and surprise (Ekman & Friesen, 1971) (Figure 2).

2.1 Basic emotions More recently, researchers interested in the detection of

deception have taken advantage of this detailed knowl-edge of characteristic muscle movements corresponding to genuine facial expres-sions to help determine when someone is lying (Gladwell, 2002).

5.2 Stress and Memory The research examining the effect of stress on human memory is limited: the ethics of psychological investigation preclude inducing in humans the levels of stress necessary to impair memory performance. However, there is some evidence that pa-tients who suffer from stress-inducing disorders, such as depression or post-traumatic stress disorder, have impaired memory, and that patients who suffer from these

disorders for a number of years show signs of hippocampal atrophy (Bremner, 2002; Nasrallah et al., 1989). Although it is difficult to test the effects of stress on human memory in a con-trolled laboratory study, it has been possible to demonstrate in humans the gluco-corticoid influence observed in rats. For instance, in one study participants were daily either administered a drug that artificially increases the level of glucocorticoids or given a placebo. After four days, participants who had taken the drug and who had elevated glucocorticoid levels showed impaired memory performance relative to participants who took the placebo (Newcomer et al., 1994). These results support the conclusion that stress hormones can impair memory if exposure is prolonged. [Smith, Edward E. and Kosslyn, Stephen M..Cognitive psychology: mind and brain]

1. The Connection In spite of the intimate relationship between emotion and cognitive processes, which we often experience consciously-"! was so furious," we say, "that I couldn't think straight"-emotion was not considered an

domain of inquiry within the study of cognition until very recently. Why has it taken so long for the study of cog-nition to include the exploration of emotion?

Reminder what is double dissociation?

double dissociation is an experimental technique by which two areas of neocortex are functionally dissociated by two behavioral tests, each test being affected by a lesion in one zone and not the other. In a series of patients with traumatic brain injury, one might find two patients, A and B.

5.1 Arousal and Memory It is well known that emotional arousal can enhance recollection. This has been shown for a number of different types of stimuli and a range of memory tasks, both in and out of the laboratory (Christianson, 1992). In a classic study, Hueur and Reisberg (1992) showed each

each of two groups of participants a different slide show with a corre-sponding narrative. Both shows depicted a mother and son going to visit the father at work. The slides and narrative at the beginning and end of each show were the same and represented neutral events, such as the mother and son leaving the house and the mother making a phone call. In one of the slide shows, the emotion condition, the mid-dle section of the story showed the father, identified as a doctor, responding to a grue-some accident. In the other slide show, the neutral condition, the father was a car mechanic. After seeing the slide show, participants were asked to recognize details of the slides and narrative. For both groups, there was no difference in the ability to re-member details of the early and late portions of the show, which depicted neutral events. Participants in the emotion condition, however, were much better at remem-bering details from the middle, emotional portion of the slide show they saw compared to participants in the neutral condition, who saw a middle part that carried no emo-tional weight.

This research is consistent with the idea that there are separate systems for emotion. However, these neural structures specialized for

emotion both influence, and are influenced by, neural systems known to be impor-tant for cognitive behaviors (Dolan, 2002; Oschner et al., 2002); the inference is that emotion and cognition are interdependent. (depending on each other)

1. The Connection Thus, both historically and in contemporary work, the prevailing models (current models_ have left little room for the investigation of the connec-tion between emotion and cognition. Nonetheless, the link between emotion and cog-nition is undeniable, and some psychologists have sought to explore its nature. One of the more recent debates (in the 1980s), which opened the door to further investi-gation of the interaction of emotion and cognition, involved the question of whether or not an

emotion could be experienced without cognitive appraisal (i.e., an in-terpretation of the reason for your feeling).

2. Defining Emotion Art and language emphasize the complexity and subtlety of emotion. But how can we define

emotion in a way that captures the range of emotional expe-rience, yet is objective and therefore can allow scientific investigation?

4.1 Classical Conditioning Studies of autonomic conditioning have revealed the importance of learned physiological responses. Studies of evaluative conditioning, on the other hand, are more concerned with learned preferences or attitudes, the subjective, emotional re-sponses that are acquired through classical conditioning. Evaluative conditioning is the goal of many (most) forms of advertising. Why do advertisers assume that pair-ing new products with attractive stimuli, such as popular athletes or celebrities, will alter our attitudes and, specifically, our purchasing decisions? We don't really think that using products endorsed by stars will confer stardom on us. Nonetheless, advertising works. It works because

evaluative conditioning works. If we experience positive affect (for example, admiration of a celebrity endorser or amusement at clever ad copy) in the presence of a neutral stimulus (a deodorant, say) we may even-tually come to prefer that stimulus. Evaluative conditioning manifests itself via a subsequent change in valence, that is, the degree to which the stimulus is regarded as pleasant (or unpleasant).

It is no longer considered ideal to study emotion without considering cognition and vice versa. The neural systems, and behavioral expression, of emotion and of cognition are interdependent in many circumstances. The understanding of cogni-tion is incomplete without

exploration of the role of emotion

4.1 Classical Conditioning Like aversive conditioning, evaluative conditioning can occur without awareness (as can be the case with advertising). In other words, a preference is acquired and ex-pressed, but we may be unaware of how this preference came to be. For example,

in one study researchers paired a series of neutral pictures with either positive, negative, or other neutral pictures (Baeyens et al., 1990). Some participants were told to search for a relationship between the members of a pair; others were told simply to look at the pictures. Participants' awareness of the relationships between the neutral and emotional pictures was then assessed. Participants were considered "aware" if they correctly indicated which emotional picture was paired with a target neutral picture; if they indicated a different emotional picture of the same valence as the one actually paired with the target neutral picture; or if, although unable to indicate a particular picture, they correctly expressed the valence of the picture paired with the target neu-tral picture. Regardless of a participant's level of awareness of the relationship, simi-lar levels of evaluative conditioning were observed. [Smith, Edward E. and Kosslyn, Stephen M..Cognitive psychology: mind and brain]

5.4 Memory for Emotional Public Events This groundbreaking study highlighted the qualitative nature of memory for emotional public events and seemed to imply that such memory is different and more detailed than other kinds of declarative memory. But the study was not par-ticularly concerned with assessing the accuracy of these flashbulb memories and such a study was not conducted until more than a decade after the assassination. Despite respondents' confidence, the accuracy of flashbulb memories has been called into question. Since this initial study, there have been investigations of mem-ory for a number of emotional public events in various parts of the world, includ-

ing the 1981 assassination attempt on Ronald Reagan (Pillemer, 1984), the Challenger space shuttle catastrophe (Neisser & Harsch, 1992), the assassination of the Swedish prime minister, Olaf Palme (Christianson, 1989), the Loma Prieta earthquake in California (Neisser et al., 1996), the Hillsborough, England, soccer disaster (Wright, 1993 ), the resignation of the British prime minister, Mar'garet Thatcher (Conway et al., 1994), and the death of King Baudouin of Belgium (Finkenauer et al., 1998). Studies examining memory for the attack on the World Trade Center in New York in 2001 have also been reported (Begley, 2002; Talaricho & Rubin, 2003). Taken together, these studies suggest that even though memory for emotional public events may be more accurate than most ordinary memories, they do not have the type of photograph-like accuracy implied by the term flashbulb memory-despite the confidence of respondents. -

4.2 Instrumental Conditioning: Learning by Reward or Punishment Thus, liking to gamble may arise from instrumental conditioning. The principle underlying instrumental conditioning (which is also known as operant conditioning)

is that a behavior or response will increase or decrease in frequency depending on the outcome of that behavior-on whether it yields a reward or a punishment. If we do something that leads to a good result (reward), we are more likely to repeat that be-havior, and if we do something that leads to a bad result (punishment}, that behav-ior is less likely to be repeated. Instrumental conditioning depends on our taking an action that can be rewarded.

2. Defining Emotion All of us, not just our artists, have a rich vocabulary for de-scribing our emotional lives:

joyful, elated, contented, delighted, cheerful, pleased, jovial, exultant, glad, blissful all describe subjective variations of the experience of "happiness.

4.1 Classical Conditoning This double dissociation between direct (explicit report) and indirect (SCR) measures of emotional learning indicates that there are at least

least two kinds of learning systems that are operating independently: one (which relies on the hip-pocampus) mediates learning accompanied by awareness, namely, the declara-tive memory system; the other (which relies on the amygdala) is necessary for conditioned autonomic responses. Additional support for the notion that aware-ness is not necessary for aversive conditioning comes from studies in which the stim-ulus linked with the aversive event is presented subliminally, so that the participant is unaware that it has been presented; this procedure can result in the expression of au-tonomic conditioning, as measured by SCR (Ohman & Soares, 1998).

4.2 Instrumental Conditioning: Learning by Reward or Punishment In an effort to understand the nature of reward, researchers have explored the neural systems of reward learning and, to a lesser degree, of punishment learning (e.g., Bornhovd et al., 2002; Delgado et al., 2000). The neural system for reward is described in terms of both a neurotransmitter, dopamine, that is linked to reward and a neuroanatomical region, the striatum. The "mesolimbic dopamine pathway"

links the ventral tegmental area of the medial forebrain bundle in the midbrain to the striatum, in the forebrain. It is this pathway that is activated in expectation of reward (Figure 8). If the ventral tegmental area is stimulated, activation of this pathway results in the release of dopamine to the striatum (Wise & Rompre, 1989).

1. The Connection In modern times, the study of cognition has been greatly influenced by the devel-opment of the computer-so much so that we speak of the "cognitive revolution" to describe the new way of thinking about cognitive processes that was based on the model of the computer. The computer provide a useful tool, a useful tool, but it is obvious that studying human information processing solely by analogy to a technologi-cal device leaves little role for

little role for emotion

4.2 Instructional and Observational Learning Like instructional learning, observational learning does not rely on direct expe-rience with positive or negative consequences. If we observe someone being re-warded or punished for a behavior, or enjoying or avoiding an event, we may learn something about the value of that behavior or event. A teacher who "makes an ex-ample" of a disruptive pupil and administers a reprimand in front of the entire class is hoping that the other pupils will engage in some observational learning. Some nonhuman animals also learn by observation. For example

monkeys raised in a laboratory free of snakes can learn to fear them by observing monkeys raised in the wild who have an intense fear of snakes (Mineka et al., 1984) (Figure 9). The neural systems for learning through observation may involve "mirror neurons." Mirror neurons, discovered in monkeys, are neurons that re-spond both when an action is observed and when that action is performed. Mir-ror neurons in the premotor cortex of a monkey fire when that animal performs a motor response and also when it observes another monkey perform-ing that response. In humans, it typically is not possible to study responses in single neurons, but by the use of neuroimaging techniques, mirror responses have been re-ported similar to those observed in the monkey (Gallese & Goldman, 1998; Rizzolatti et al., 1996). Moreover, researchers have discovered mirror responses for emotion. Watching someone else experience pain results in activation of parts of the pain circuitry in the observer (Singer et al., 2004 ). In an effort to extend this finding to observational learning, participants were told to watch a film clip of a confederate of the investigator undergoing classical conditioning in which a blue square is paired with a mild shock to the wrist. The participants were then presented with blue squares, but never actually received a shock. The amygdala, which we know is important for fear conditioning and instructed fear, also responded when partici-pants observed the confederate respond to the shock paired with the blue square. The magnitude of amygdala activation during observation was the same as when the participants were presented with the blue square and were anticipating the shock themselves (Olsson et al., 2004)

Mood is related to attitude and motivation What is motivation?

motivation refers to the propensity to action that is a component of some affective responses. When you watch a horror movie, at fearful moments you may hide your eyes to escape the image on the screen. A primary function of emotion is to motivate action (if the image on the screen had been real, your action in response might have been of larger scale, and you might have survived to see another day).

4.3 Instructional and Observational Learning In fact, learning to fear through instruction and through classical conditioning activate some of the same neural pathways.

n particular, the amygdala is not only important in aversive conditioning, but also plays a role in the physiological expression of instructed fear learning. This finding resulted from a study designed to be as similar as possible to the fear conditioning study described earlier in which patient S.P. participated. The difference is that shock was paired with the blue square only through verbal instruction. Patients with right or left amygdala dam-age as well as normal participants were told that they might receive a mild shock to the wrist when a blue square is presented ("threat"), but they would never re-ceive a shock when a yellow square was presented ("safe"). Even though none of the participants in fact received a shock, the normal participants and those with right amygdala damage showed a potentiated startle response during presenta-tions of the blue square, indicating a negative emotional response to the blue square-threat stimulus. The participants with left amygdala damage, however, did not demonstrate potentiated startle to the blue square (Funayama et al., 2001), in-dicating that the left amygdala is involved in instructed learning to fear. Although only the left amygdala plays a role in the expression of instructed fear, perhaps be-cause of the verbal nature of instructed learning, these results suggest that the amygdala plays a role in the expression of fears that are imagined and anticipated, but never actually experienced. A related study using £MRI data from normal par-ticipants was reported by Phelps et al. (2001). Both these studies are examined in the accompanying A Closer Look.

5.1 Arousal and Memory Regrettably for our peace of mind, memories for embarrassing situations may not fade. It would be nice to forget those occasions when our ignorance or social awkwardness was on full display. But we don't forget these events, and sometimes other people don't either. Why are these moments when you'd like to sink through the floor selected to last (and last vividly) and others are not? One reason is that embarrassment, an emo-tional reaction, leads to arousal, and arousal enhance

our ability to store memories.

1. The connection The dingle mostinfluential factor in this new focus is our..

our growing under-standing of the neural systems underlying emotion. It now appears, from neu-roimaging and other brain-based studies, that some brain structures are more or less specialized for processing emotional stimuli. One of these is the amygdala, a small, almond-shaped structure in the medial temporal lobe just anterior to the hippocam-pus (LeDoux, 1996) (Figure 1). This research is consistent with the idea that there are separate systems for emotion.

4. Emotional learning Acquiring Evaulation Understanding how stimuli acquire affective value is interest to wide range of:

professions, advertising and animal training among them. For psychologists, un-derstanding how a stimulus becomes associated with an emotion is a central chal-lenge in the investigation of the interaction of emotion and cognition. There are several means by which a stimulus can acquire emotional significance.

2. Defining Emotion Many have argued that the essential appeal of the arts is the

subtlety and power with which emotion can be expressed by the artist and evoked in the spectator-it is the essence of Aristotle's conception of tragedy. Shakespeare certainly knew the intrigue of complex emotional lives; his aim, in his words, was "to hold, as 'twere, the mir-ror up to nature," and he portrayed those emotions in his plays. A great opera com-bines dramatic scenarios and sublime music to heighten the emotional experience of the audience. And a great rock song does more than get your feet tapping-it also tugs at your emotions.

5.3 Mood and Memory Mood-congruent memory effects are not always found. For example

tests of recognition memory ("Did you see this word before?") are less likely than tests of recall ("What was the word you just saw?") to elicit mood-congruent memory effects (Bower & Cohen, 1982). In addition, although mood-congruent memory effects have been found for both positive and negative moods, they are stronger for positive moods. This may reflect a tendency toward more creativity and generative activity with positive moods (Fiedler et al., 2001).

2.2.2 The Approach - Withdrawal Disintinction The approach-withdrawal model characterize

the component of an emotional re-action that is the propensity to action-that is, motivation-as either a tendency to approach the object, event, or situation or to withdraw from it

4.1 Classical Conditioning The name most often associated with classical conditioning is that of Ivan Pavlov (1849-1936),

the great Russian physiologist who discovered the principles of such conditioning. Pavlov was interested in digestion and intended to examine salivation in dogs in response to food. His studies became complicated when the dogs started to salivate before the food was presented: the salivation response was occurring when a researcher opened the door to the dogs' quarters. The dogs were salivating in response to an event associated with the presentation of food. Pavlov realized that reflexes such as salivation can be evoked not only by the appropriate stimuli (in this case, food), but also by events associated with these reflex-inducing stimuli. Further research has demonstrated that all sorts of reflexes and responses, including emo-tional responses, can be elicited by conditioning.

4.1 Classical Conditoning Specifically, when participants were asked to rate how much they liked the neu-tral pictures, those who had been unable to report any knowledge of the relationship between the target neutral pictures and their respective pairs showed levels of ac-quired preferences similar to those of participants who were completely aware of the relationship between pictures. This attitude formation can occur independently of awareness. In addition, results consistent with this idea were obtained in two studies conducted with amnesic participants, who have deficits in declarative memory. Pref-erence formation was demonstrated even though

these patients were unable to re-port any memory for the conditioning procedures (Johnson et al., 1985; Lieberman et al., 2001).

2.2.1 Circumplex model Both arousal and valence dimensions can be put on scales,

you can be asleep, relaxed, or highly excited, you can be terrifically pleased, indifferent, or highly turned off-and anything in between.