Lecture 3- Attention and Performance
What is the cocktail party problem? (Cherry 1953)
- How do we focus on one conversation at a time? Used a dichotic listening task, in which a different auditory message is presented to each ear and the listener typically attends to only one. Since it can be hard to ensure listeners are consistently attending to the target message, Cherry made use of shadowing, in which the attended message was repeated aloud as it was presented.
What is the traditional approach to automatic processing? -What are automatic processes?
- No capacity limitations - Do not require attention - Hard to modify once learned -However very specific to the task you are doing- inflexible. Autonomic processes function rapidly and in parallel but suffer from inflexibility.
What determines how well we can perform two tasks at the same time? (dual-task performance)
- Similarity between tasks modality • e.g. visual vs auditory - Similarity between responses • e.g. manual vs vocal
How did Cherry (1953) suggest that we can focus on one conversation at a time?
- Using physical differences (e.g. gender, location). When Cherry presented two messages in the same voice to both ears at once (thus eliminating these physical differences), listeners found it very hard to separate out the two messages on the basis of meaning differences alone. Physical changes were nearly always detected. - Extract little information from unattended stimulus. Listeners seldom noticed when the message was spoken in a foreign language or reversed. - Exogenous (stimulus-driven), as hear salient information in unattended stimulus
-When is attention active? -When is it passive?
-Attention is active when controlled in a top-down way by the individual's goals or expectations -Attention is passive when controlled in a bottom-up way by external stimuli (eg. a loud noise)
What are the two important attentional disorders?
-Can learn much about attentional processes by studying brain-damaged individuals. Two important attentional disorders: • Neglect (or spatial neglect) - Lack of awareness of stimuli presented to side of space on the opposite (or contralateral) side to the brain damage- consequence of anatomy • Extinction - Often found in patients with neglect - Failure to detect a stimulus presented to the side opposite the brain damage when a second stimulus is presented to the same side as the brain damage
What is the differences between change and inattentional blindness?
-Change blindness and inattentional blindness are similar in that both involve a failure to detect some visual event that appears in plain sight—failures of attention, for example, often play an important role in causing both forms of blindness. However in spite of these similarities, there are major differences between the two phenomena. • Unlike inattentional blindness, for change blindness to occur they must successfully enage in 5 separate processes: - Attention must be paid to the change location - The pre-change visual stimulus at the change location must be encoded into memory - The post-change visual stimulus at the change location must be encoded into memory - The pre- and post-change representations must be compared post-change representations must be recognised at the conscious level Jensen et al. (2011) -In sum, more complex processing is typically required for successful performance in change blindness tasks than in attentional blindness ones
What is the difference between external and internal attention?
-Important distinction between external and internal attention. External attention refers to "the selection and modulation of sensory info". Internal attention refers to "the selection, modulation, and maintenance of internally generated information, such as task rules, long term memory etc."
What did Posner (1980) do in their research?
-Studied covert attention, in which attention shifts to a given spatial location without an eye movement. -In his research, participants responded rapidly to a light • Select the side a flash of light is presented. Had to say whether the flash was to the left or right - Left/right of a central fixation cross • Flash preceded by a central cue (arrowing pointing to the left or right): - Arrow correctly points to flash location (valid cue) - Arrow incorrectly points to flash location (invalid cue) OR • Flash preceded by a peripheral cue (brief illumination of a box outline): - Outline of shape in flash location (valid) - Outline of shape opposite side of flash location (invalid) -Valid cues indicate where the target light would appear -Invalid cues provided inaccurate information about the light's location
What causes change blindness?
-The main reason is that change detection requires the successful completion of 5 different processes. Change blindness often depends on attentional processes. We typically attend to regions of a visual scene most likely to contain interesting or important information. -Hollingworth and Henderson (2002) studied the role of attention in change blindness, and found that change detection was much greater when the changed object had been fixated prior to the change. There was very little evidence observers could accurately detect change in objects not fixated prior to change. • No single (or simple) answer! - Representations may be incomplete due to limited attentional focus - Representations may decay or be overwritten. Memories decay over time, or overwritten by another stimulus. - Representations of pre-change stimulus may be limited to the unconscious - Impossible to compare pre- and post-change - Perceptual accuracy sacrificed so that we have continuous and stable perception of environment
What is the ventriloquism effect?
-What happens when there is a conflict between simultaneous visual and auditory stimuli? -Ventriloquism effect is when sounds are misperceived as coming from their apparent visual source. -Ventriloquists speak without moving their lips while manipulating the mouth movement of a dummy. It seems that the dummy rather than the ventriloquist is speaking.
What is the first processing stage associated with feature integration theory?
1. Basic features processed rapidly and pre-attentively in parallel across visual search Applies when Targets defined by a single feature -Targets defined by a single feature should be detected rapidly and in parallel
What are the conditions that need to be satisfied for the ventiloquist illusion to occur?
1. The visual and auditory stimuli must occur close together in time 2. The sound must match expectations raised by the visual stimulus 3. The sources of the visual and auditory stimuli should be close together in space. -The ventriloquism effect is an example of visual dominance
What are the 2 major theoretical approaches to automatic processing?
1. Traditional approach (Shiffrin & Schneider, 1977) 2. Definitions of automaticity (Moors & de Houwer, 2006)
What are the 4 factors associated with automaticity according to definitions of automaticity?
1. Unconscious: lack of conscious awareness of the process. Because no significant processes intervene between the presentation of a stimulus and retrieval of the appropriate response. 2. Efficient: using very little attentional capacity. Because the retrieval of heavily over-learned information is relatively effortless. 3. Fast. Because they require only the retrieval of past solutions from LTM. 4. Goal-unrelated: uninfluenced by the individual's current goals • Not always found together - e.g. can be partially conscious or fairly fast/slow •Also argued that there is no firm dividing line between automaticity and non-automaticity. The features are continuous rather than all-or-none—as a result, most processes involve a blend of automaticity and non-automaticity
What are the 4 interrelated ideas of attention?
1. We are constantly confronted with more information than we can attend to 2. There are serious limitations in how much we can attend to any at one time 3. We can respond to some information and perform some tasks with little if any attention 4. With sufficient practice and knowledge, some tasks become less demanding of attention -Focused attention related to the first 2 ideas
What is the second processing stage associated with feature integration theory?
2. Slower serial process with focused attention providing the "glue" to form objects from the available features. When we are combing features attention is involved. Speed and accuracy depends on the number of distractors. Applies when Targets defined by a combination (or conjunction) of features -Targets defined by a conjunction or combination of features should be slower to detect and should require attention
• Can neglect patients process unattended visual stimuli in the absence of conscious awareness of those stimuli?
awareness of those stimuli? -Asked to respond as quickly as possible when they see a dog -Suggests that patients with neglect are unconsciously processing the stimuli without conscious awareness
Who came up with feature integration theory?
Treisman & Gelade (1980) Treisman (1990) -Within the theory there is an important distinction between object features (eg. colour, size) and the object themselves.
Why is attention important?
• Attention is important and helps us to: - Focus on a specific object to gain more information - Bind (or integrate) features together so we can perceive a coherent object - Ignore unwanted distraction • Is our ability to perceive compromised in the absence of attention?
What is cross-modal attention?
• Coordinate information from two or more modalities simultaneously -Before the visual or auditory modality were studied on their own. In the real world, however, we often coordinate information from two or more sense modalities at the same time.
What causes inattentional bias?
• Depends on probability that unexpected object attracts attention • Two factors of importance: 1. Similarity of unexpected object to task-relevant stimulus o Black gorilla - ignore team dressed in black, whereas count passes between team dressed as white. Observers counted the pasess made by the members of the team dressed in white or the one dressed in black. o More likely to see gorilla when counting passes between team dressed in black. This shows the importance of similarity between the unexpected stimulus (gorilla) and task-relevant stimuli (members of attended team). Also indicate the importance of similarity in stimulus features (eg. colour) between task stimuli and the unexpected object. 2. Observer's available processing resources
How are we able to engage in focused attention?
• Eye movements - Move eyes so that input of interest falls on the central fovea - Motion triggers reflex of movement • Head movement - Position ears for better hearing
What is inattentional bias?
• Fail to notice an unexpected, but fully visible item when attention is diverted to other aspects of a display - Simons & Chabris (1999)
What is change blindness?
• Failure to detect (obvious) changes in the environment -Simons & Levin (1998) -Eg. Experienced at movies when there has been unintended continuity mistakes when a scene has been shot more than once. Eg. in the Bond film Skyfall, in one scene Bond is in a car being followed by a white car. Mysteriously, this car becomes black in the next shot, and then returns to being white.
What is visual search?
• Indicate as quickly as you can whether a particular target is present • Takes longer and requires more attention when searching for a combination (or conjunction) of features
What is focused auditory attention?
• Lessons learned from vision applied to our sense of hearing • Select sounds of interest, while ignoring others • Must separate (or segregate) different auditory stimuli
What did Posner find when they manipulated the experiment so that the majority of cues were invalid? -Does this give us evidence for seperate exogenous and endogenous networks?
• Majority of cues invalid- expectation that the cues are not going to tell us where the flashes are - Central cues = RTs same for both valid/invalid - Peripheral cues = RTs still faster for valid trials -When the cues were valid on only a small fraction of trials, they were ignored when they were central cues but influenced performance when they were peripheral cues. This finding led Posner to distinguish between the 2 systems. • Separate exogenous and endogenous systems- evidence for separate attentional networks - Expect that cues should be ignored (i.e. do not cue the correct location the flash) - Endogenous attention used when central cues present and controlled by expectations - Exogenous attention used when peripheral cue present and stimulus-driven
What did Posner find when they manipulated the experiment so that the majority of cues were valid? -Does this give us evidence for seperate exogenous and endogenous networks?
• Majority of cues valid - Central cues = RTs faster for valid cues - Peripheral cues = RTs faster for valid cues • Separate exogenous and endogenous systems? -This evidence alone doesn't provide evidence for exogenous and endogenous networks - Expect that cues are reliable (i.e. correctly cue the correct location of the flash) - Endogenous attention used when central cues present and controlled by expectations - Exogenous attention used when peripheral cue present and stimulus-driven
What is attention?
• Mental process of concentrating effort on a stimulus
What are illusory conjunctions?
• No difficulty perceiving features on display • However, unsure how features are combined • Report illusory conjunctions -People confuse the colours of letters at the end, when they are distracted by remembering a list of words -When your attention is distracted, you are unlikely to focus your attention to remember what is on display- need attention to remember information
What is automatic processing?
• Practice makes perfect! -The processing becomes much more automatic- cutting out the extra process of attention • Assume that processes become automatic -A key finding in studies of divided attention is the dramatic improvement practice often has on performance. This improvement has been explained by assuming some processes become automatic through prolonged practice.
What is divided attention?
• Present two stimulus inputs at same time • Must attend and respond to ALL inputs • Also known as multi-tasking • Tells us the capacity of attention -Studied by presenting at least two stimulus inputs at the same time. However, it differs from focused attention in that individuals are instructed they must attend (and respond) to all stimulus inputs. -Studies provide useful info about our processing limitations and the capacity of attentionak mechanisms.
What do definitions of automaticity reject about the traditionalist approach?
• Reject assumption that clear-cut distinction between controlled and automatic processes
What is focused attention?
• Select one input while ignoring all others -Focused attention is studied by presenting individuals two or more stimulus inputs at the same time and instructing them to respond to only one. Eg. a predator who keeps track on one animal in a flock -Work on focused attention tells us how effectively we can select certain inputs and avoid being distracted by non-task inputs.
What is the McGurk effect?
• The McGurk effect - Sound same in both clips • Further evidence for visual dominance - Input from vision influences auditory perception -Tendency for visual sphere to dominate what we can hear
What is neglect? -Object-centered -Subject-centered
• Typically involves right-hemisphere damage in which the left side of objects and/or objects presented to the left visual field are undetected • Object-centred (allocentric) - Lack awareness of side of objects • Subject-centred (ego-centric) - Lack awareness of entire side of visual field. The brain damage is typically in the right hemisphere and there is often little awareness of stimuli on the left side of the visual field. -It occurs because of the nature of the visual system: information from the left side of the visual system proceeds to the right hemisphere. When patients canacel targets presented to their left or right side (cancellation task), they generally cross out more of those presented to the right. When patients try to put a mark through a horizontal line at its centre (line bisection task) they typically put it to the right of the centre.
Example of divided attention in the real world
• Using a mobile phone (handheld or handsfree) when driving - Four times more likely to experience an accident • Why does using a mobile impair driving ability? - More likely to focus on the road ahead (central cues) less likely to see peripheral objects - Mobile phone use on driving effects general attentional processes
What is the traditional approach to automatic processing? -What are controlled processes?
•Controlled processes - Limited capacity - Require attention - Used flexibly in changing circumstances -Can be generalised --Controlled processes are flexible and versatile but operate relatively slowly and in a serial fashion.
