Exam 1 study guide cognitive psychology

pandemonium model

A feature-based object recognition scheme involving a population of 'demons' each with a particular task. Feature demons signal the presence of features in an image; cognitive demons look for feature combinations; finally, a decision demon selects the most active cognitive demons.

models of HIP

Encode compare decide respond STM and WM LTM

lab 5- Brown peterson task

In the 1932, John McGeoch wrote an extremely influential critique of theories of forgetting, and for the next 25 years or so, no researcher viewed decay as a viable explanation of forgetting. Instead, memory loss was considered to be the result of interference. In the late 1950s, two groups of researchers (one named Brown and a husband and wife team named Peterson) published data that forced a new interpretation of human memory. In the memory task, the participant saw a "consonant trigram" (three such as GKT or WCH) and then engaged in a distractor task. The purpose of the task was to prevent rehearsal, and the task chosen was counting backwards by 3 or 4 from a 3-digit number. The distractor task lasted between 3 and 18 s. The data showed that the probability of correctly recalling the trigram decreased as the length of the distractor task increased. Solving math problems seems to be very different from recalling consonant trigrams, so it was unlikely that there was any interference to disturb the memory of the trigram. The conclusion was that there exists a short-term memory (STM) system that holds information for several seconds. Without an active effort by the participant, information in STM fades away (but see Keppel & Underwood, 1962, for an alternate explanation). Performing the distractor task prevented the participant from actively rehearsing the trigram. This lab is based on the original Peterson & Peterson (1959) study, but with a few changes. You will be asked to count backwards only by 3s, and the delay durations are 3, 6, 9, 12, and 15 s. You should find the counting backward task to be difficult because it is: it is designed to be hard enough that you are not able to rehearse the letters.

lab 4- change detection

Look carefully at the animated picture on the right. It shows a street in Vancouver, Canada, alternating with a light gray background. (If you don't see this, you may need to adjust the settings in your browser to allow animated gifs.) There are actually two different photographs of the road. Can you spot what is changing? Chances are, you don't see anything changing right away, and it should take you a while to spot the change. Once you know what to look for, however, the change is obvious. (The answer is at the bottom of this section.) The picture illustrates change detection (Rensink, 2002) or, more accurately, how difficult it can be to detect change. The basic idea is that people do not store many details of a scene in memory. Rather, the critical factor seems to be attention: In order to see an object change, it is necessary to attend to the object. The animated image illustrates Rensink's flicker paradigm in which an original image is followed by a blank image (a mask) and is then followed by a changed image (and another mask). This is usually referred to as the "flicker" condition, because the images sometimes appear to be flickering. The blank image swamps the local-motion signal that would ordinarily be caused by a change in an object, so attention is not drawn to the change. The presence of the mask prevents automatic detection of change. Change must now be detected by a slower, higher-level process. Basically, you have to search the scene, object by object until you happen to find the changed object. Failing to detect that an object has changed has been called change blindness. Researchers think that change blindness is a leading cause of many car accidents. Glancing away from the road and then back is equivalent to seeing a scene, followed by a blank field followed by a changed scene: The change is very difficult to notice, so your car hits another car.

Lab 6- word length effect

Many theories of cognition propose that there is a short-term or working memory system that is able to hold a limited amount of information for a short period of time. One finding that was instrumental in the development of working memory was the word length effect: people recall lists of short words more accurately than lists of long words. The initial idea was that people rehearse the items over and over. If you assume that rehearsal rate is relatively constant, then you should be able to rehearse short words (e.g., dog) more often than long words (e.g., hippopotamus). This led to the idea that the capacity of working memory is more likely based on time (e.g., how much you can say in about 2 seconds) than on items (e.g., how many items can you store). The reason is explored in this lab.

lab 2- signal detection

Much of cognitive psychology involves gathering data from experimental participants. Gathering good data is not always easy, especially when an experiment uses a variety of people as participants. Researchers must carefully design an experiment to be certain that participants are following the instructions and are motivated to try their best. Even despite these efforts, experimental results can be contaminated by individual differences if the researcher does not properly analyze the data. For example, consider two participants in visual detection of a faint target. The researcher wants to explore a property of the visual system, so he/she presents a visual stimulus and asks the participants to report whether they saw the target. After 50 trials, Participant A reports seeing the target 25 times and Participant B reports detection 17 times. Did Participant A do better? Not necessarily, perhaps Participant A is simply more prone to report seeing the target whereas Participant B is more conservative and requires more evidence before reporting a target. That is, the two participants may have equivalent visual systems, but differences in their criterion for reporting. Reports of simple detection do not allow the researcher to compare participants' results. A better experiment is a modification of the one above and has two kinds of trials, one with the target present and one with the target absent. Again, the participants report whether they saw the target. There are four statistics to be calculated from this experiment. (1) A hit is when the participant correctly detects the target. (2) A miss is when the target was there but the participant did not detect it. (3) A false alarm is when the participant reports seeing the target when it was not actually there. (4) A correct rejection is when the participant correctly reports that the target was not present. Suppose that after 100 trials (50 for target present and 50 for target absent) the researcher again finds that on the trials in which the target was in fact present, Participant A reports seeing it 25 times and Participant B 17 times. Who is doing better? It depends on the frequency of false alarms. If Participant A has 25 false alarms and Participant B has 5 false alarms, then B is better than A at distinguishing the trials in which the target is present from the trials in which the target is absent. That is, in this case, A tends to guess that the target is there, but she/he is wrong (a false alarm) as often as she/eh is correct (a hit). B is more selective about saying he/she detects the target, but rarely says the target is there when it is not. Thus, B is doing better. This type of analysis suggests that you need to consider two numbers, hits and false alarms, to really be able to compare performance across participants. Fortunately, you can combine the numbers in a careful way to produce a single number that gives an indication of the sensitivity of the participant to the presence of the target. The calculation is structured so that, with certain assumptions, it will not matter whether a participant takes a conservative or liberal approach to claiming to detect the target. The most common measure of sensitivity is called d' (d-prime), and a common measure of bias (whether the person took a conservative or liberal approach) is called C. A discussion of the algorithms for calculating sensitivity is beyond the scope of this experiment (see Macmillan & Creelman, 1991, for further discussion). This lab provides an experiment that measures sensitivity (d') and bias (C).

lab 3- simon effect

The Simon effect refers to the finding that people are faster and more accurate when responding to stimuli that occur in the same relative location as the response, even though the location information is irrelevant to the actual task (Simon, 1969). Studying the Simon effect gives us insight into a stage of decision making called "response selection." According to information-processing theory, there are three stages of decision making: stimulus identification, response selection, and response execution or the motor stage. Superficially, the Simon effect may seem similar to the Stroop effect. However, it is generally accepted that the interference that occurs in the Stroop effect comes from the stimulus identification, while the interference that occurs in the Simon effect occurs in the response-selection stage. During response selection, a person uses a rule to translate the relevant stimulus dimension, usually shape or color, to the correct left or right response. However, the location dimension of the stimulus (its position on the screen) overlaps with the relevant stimulus dimension (left or right). Because of this, the irrelevant location dimension of the stimulus activates the corresponding response and interferes with making a response to the non-corresponding side. As a result, same-side responses are faster and more accurate than opposite-side responses. In the real world, the Simon effect has important implications. Primarily, it shows that location information cannot be ignored and will affect decision making, even if the user knows that the information is irrelevant. The Simon effect (and related phenomena) must be taken into account in design of man-machine interfaces. Good interfaces display information in ways that match the types of responses people should make. For example, imagine that you are flying a plane, and the left engine has a problem. The indicator for that engine should be to the left of a corresponding indicator for the right engine. If it is the other way around, you may respond incorrectly to the indicator and adjust the wrong engine. That could be problematic.

lab 1 - brain asymmetry

You may have heard that each person has two distinct hemispheres of the brain, each with different capabilities. For example, the sensory signals from the left side of your body are sent to the right hemisphere of your brain and the sensory signals from the right side of your body are sent to the left hemisphere of your brain. Likewise, control of your right arm and leg is via your left hemisphere and control of your left arm and leg is via your right hemisphere. More notable cognitive differences also exist. The left hemisphere is said to deal with language and analytical thought, while the right hemisphere is said to deal with spatial relations and creativity. The basis for these claims about cognition comes from investigations of clinical patients who, usually to control a serious case of epilepsy, underwent surgery that separated their left and right hemispheres. (This surgery prevented epileptic seizures from passing from one hemisphere to the other.) Careful studies of these split-brain patients revealed fascinating properties about how the brain was organized. A patient asked to fix on a spot on a screen could verbally report words flashed on the right side of the screen. (Those words were sent to the left hemisphere.) The patient could not say the word if it was flashed on the left side of the screen (thus sent to the right hemisphere). Notably, the patient could identify, by picking up with the left hand, a physical item matching a word flashed on the left side of the screen. Subsequent work showed a variety of differences between the brain hemispheres, and some researchers concluded that even people without split brains effectively have two competing brains. These conclusions were picked up by the popular press, and one now sees a variety of claims that schools should nurture one brain side instead of another, or that different types of therapy should be used to strengthen an undeveloped hemisphere. As it turns out, many experiments fail to find much difference at all between the two hemispheres in individuals without split-brain surgery. This is not to suggest that there are no differences, but the functional significance of these differences may be very slight. Moreover, when such differences do exist, they tend to be strongest for right-handed males. Females and left-handed individuals tend to not show brain-side effects nearly as strongly. This lab is based on as study by Federmeier and Benjamin (2005). Words are presented to the right visual field (which sends information to the left hemisphere) and to the left visual field (which sends information to the right hemisphere). They tested only right-handed individuals and found a slight memory advantage for words shown to the right visual field (i.e., left hemisphere).

stm span

a bit is the amount of information contained in a stimulus. from a bit came chunks, theorized that we can hold 7 +/- 2 chunks of information- time it takes information to be transferred to LTM is related to number of chunks, not number of characters or words in the set- Miller

partial report procedure

a task in which observers are cued to report only certain items in a display of items

whole report procedure

a task that requires observers to repeat everything they see in a display of items

direct memory test

a test that asks people to recall or recognize past events

indirect memory tests

a test that does not explicitly ask about past events but is influenced by memory of past events

Neisser's definition of cognitive psychology

all processes by which sensory input is transformed , reduced, elaborated, stored

theories of attention

cherry: selective attention broadbent: sensory filter theory: all information comes in and is passed through a sensory filter that selects information based on its physical characteristics. people could identify their name in unattended channel- suggests that unattended messages are processed Deutsch and Deutsch and Norman: response selection theory: assumes we process all information to the point of identification, and then a pertinence mechanism kicks in to determine which of this information deserves further processing- increases the baseline activation of relevant information. theory has easier time being transferred to STM. Limits number of responses that an individual can make. We are not limited in the number of responses that we can make, at least from different channels. Shiffrin and schneider: limided capacity processing theory: a limited capacity processor in the system produces a bottleneck, resulting in 2 types of processing (automatic and controlled)

duration of stm

decay: theory that infromation is spontaneously lost over time, even when there is no interference from other material interference: theory that forgetting occurs because other material interferes with the information in memory if you speed up the rate of presentation you can see if it is decay or interference about 30 seconds

searching for items in a perfect and not so perfect environment

example of kitchen, cut up scene into small pictures, makes it harder because it is not in context or a conceptual whole

top down processing

flow of information from long term memory toward the sensory store. conceptual information

bottum up processing

flow of information from the sensory store towards the long term memory. raw sensory information.

retroactive interference

forgetting that occurs because of interference from material encountered after learning

proactive interference

forgetting that occurs because of interference from material encountered before learning

codes in STM

have codes for all senses. The more codes you activate the better you will remember stm is affected by articulacy/acoustic codes (errors in stm based on verbal/sound confusion) as well as semantic codes (RPI) and imaginary codes and dual coding, mental rotation Baddelt: working memory is a limited capacity system for temporary storage and manipulation of information for complex tasks such as comprehension, learning, and reasoning 3 components -phonological loop: hold verbal /auditory information, has 2 components (storage/rehearsal) -central executive: pulls information from LTM, coordinates phonological loop and visual spacial sketch pad by focusing on specific parts of a task and switching attention from one to another -visual spacial sketch pad: holds visual/spacial information (ie forming a picture in your mind, solving a puzzle, finding your way around campus)

missing info in the environment that we can clearly "see" and "hear"

ignoring everything around you when you are focusing on one particular thing

controlled processing

mental operations that demand a lot of mental effort

dichotic listening/cocktail party effect

one message in one ear and one in the other, unattended message unnoticed even if the language changes ability to focus on one message in the barrage of sound at a party. selective attention personally. relevant information

automatic processing

performing mental operations that require very little mental effort

visual agnosia

person can see but cannot recognize or interpret visual information due to a disorder in the parietal lobes

recall curve information

serial position effect: ability to recall words at the beginning and end of lists primacy effect: the better recall of words at the beginning of a list recency effect: the better recallof words at the end of a list

importance of shadowing

shadowing doesn't allow you to rehearse. information still comes in from unattended channel

theories of pattern recognition

template matching: unanalyed pattern that is matched against alternative patterns by using the degrees of over lap as a measure of similarity. if the match is not perfect, we may adopt a criterion of, for instance 80%. If we have a match that is 80% or better, then we identify the stimulus prototypes: flexible template, idealized representation. They result from our constant abstraction of common characteristics from various instances of an object or concept. prototypes are idealized representations and no match is ever 100% perfect feature matching: describes patterns in terms of their parts or features. some argue that it is more parsimonious to do a feature analysis on new information in order to identify it rather than try to match templates or prototypes. we store lists of features for objects along with the label in the LTM. We identify objects based on an analysis of distinctive features, like how we identify letters of the alphabet.

searching STM (sternberg)

test digit was sequentially compared with each item stored in stm and that it required about 38 msec to make each comparison. The time required to make the decision increased as a linear function of the number of the digits in stm, Three types of searches -self terminating: best -exhaustive search -parallel search (automatic search)

word superiority effect

the findings that accuracy in recognizing a letter is higher when the letter is in a word than when it appears alone or is in a nonword. Early attempt to test top down and bottom up processing

memory span

the number of correct item that people can immediately recall from a sequence of items

impact of case studies

to understand cognitive processes

capacity of LTM

unlimited