1. Cognition – 2/e Dr. Daniel B. Willingham
Chapter 3: Attention
PowerPoint by Glenn E. Meyer, Trinity University
©2004 Prentice Hall

2. Attention
Definition: The mechanism for continued cognitive processing. All sensory information receives some cognitive processing; attention ensures continued cognitive processing.
Two Properties of Attention
Attention is limited in some fashion. Cognitive processing cannot occur for all stimuli simultaneously
Attention is selective - you can expend your mental energy on a cognitive process as you see fit
© 2004 Prentice Hall

3. In What Way Is Attention Limited?
Parallel Performance
Consistent Attention Requirements
Allocation of Attention
Reduction in Attentional Demands with Practice: Automaticity
© 2004 Prentice Hall

4. Parallel Performance
Attention can be distributed to more that one task at a time - multiple tasks can be done in parallel
Tested with the Dual Task Paradigm using continuous tasks rather than discrete tasks to avoid switching from task to task
Dual task: A method of examining attentional demands. The target task is performed alone and in the presence of a secondary task; if the target task requires little or no attention, performance should not deteriorate when the secondary task is added.
Continuous task: A task in which there is no obvious beginning and ending to each trial; there is a continuous stream of stimuli and responses (e.g., a pursuit tracking task). Ex. - touch typing
Discrete task: Each trial has a discrete beginning and ending (e.g., a simple response time task). Ex. - simple reaction time to a light
However, it is difficult even with dual task paradigms to guarantee parallel performance as compared with task switching - Broadbent (1982), Welford (1980), Salthouse (1984)
© 2004 Prentice Hall

5. Consistent Attention Requirements
When performing multiple tasks, does the amount of attention assigned to each task remain constant? Probably not.
Multiple Resource Theories: Attention is thought to be composed of number attentional pools, dedicated to a different type of task (Navon & Gopher, 1979; Norman & Bobrow, 1975)
One suggestion - pools separated on basis of sense modality - Navon and Gopher (1979)’s analysis of Brooks (1968) simultaneous spatial and vocal tasks. Same modality task interfere more than cross modality.
Not supported by Driver and Spence (1994) as seen in Fig. 3.4 Audition and vision not completely separate
Wickens (1984, 1992) - pools of attention based on dimensions of task
Perceiving the stimulus/ selecting the response
Verbal or spatial processing used
Modalities of input/output
While appealing multiple resource pools have been difficult to specify in a usual predictive manner. It is not clear how many pools exist or how they are related to tasks - Allport, 1989; Luck and Vecrea, 2002.
© 2004 Prentice Hall

6. Allocation of Attention
Psychologist assume people can allocate more or less attention to a task according to their goals - Example: when driving becomes difficulty you stop talking to your friend.
Experimental test - Sperling and Melchner (1978)
Subjects view inner set of four letters surrounded by 16 letters
Arrays flashed on computer screen, containing two digits that have to be reported as to identity and location
Subjects told to allocate 90% of attention to one array or the other
As seen in Figure 3.3, when subjects attend to an array, they get most of the digits correct
Attention allocation seems to be demonstrated
© 2004 Prentice Hall

7. Reduction in Attentional Demands with Practice: Automaticity
Automatic process: A process that takes few or no attentional resources and that happens without intention, given the right set of stimuli in the environment. For ex.: Some aspects of driving a car.
Two characteristics of automaticity:
Requires little or no attention
Happens without intention
Automaticity and Attention
Schneider and Shiffrin (1977)
Search for targets with consistent or inconsistent distractors
Consistent distractors led to pop-out of targets. Indicates search is automatic.
When targets was selected from same set on each trial, automaticity developed over many trials as seen in Fig. 3.6
Exact mechanism of the development of automaticity is under debate - Anderson, 1983; Newell and Rosenbaum, 1981; Willingham, 1998.
Logan (1988, 2000) suggests automaticity related to increase in use of memory in task.
© 2004 Prentice Hall

8. Automaticity - Continued
Automaticity and Inattention
Automatic processes can happen beyond our control but one must be cautious in interpretation
Two Examples:
Stroop test -- Try to say the color of each word - not the word itself.
Interfering Noninterfering
Suggests reading is automatic
Flanker Effect (task) - Stimuli (usually words) that appear to the sides of a target and that participants are to ignore, affect behavior.
Dallas and Merikle (1976) - reading a target word faster when flankers semantically related
Shaffer & Laberge (1979) - categorization faster with related flankers
We still must consider what elicits automatic response. When walking and you see a red light - you don’t make a braking movement with your foot.
RED GREEN
GREEN RED
YELLOW BLUE
BLUE YELLOW
© 2004 Prentice Hall

9. What is the Fate of Sensory Stimuli that Are Not Selected to Receive Attention?
Early Filter Theories
Later Filter Theories
Movable Filter
What is Selected?
How Does Selection Operate?
© 2004 Prentice Hall

10. Early Filter Theories
First studies - Cherry (1953) using dichotic listening and shadowing tasks
Participants listen to material on headphones, and each earpiece plays a different message (dichotic listening). They attend to one message and must shadow that message. Shadowing means repeating the attended message aloud as they hear it. Task used to study how much the unattended material is processed
Participants didn’t notice:
If the unattended message switched languages
If the unattended message was played backwards
Participants did notice:
If the unattended message became a pure tone
If the unattended message switched gender
If the unattended message was repeated 35 times (Moray, 1959)
Cherry concluded that the unattended message was not analyzed for meaning, only for physical characteristics.
Broadbent (1958) - One of the first Early Attentional Filter Models
Information first enters very brief sensory store
Filter occurs after this store
Small portion of information sent to the next stage of primary memory
Primary memory: awareness and assignment of meaning
© 2004 Prentice Hall

11. Late Filter Theories
Problem with Broadbent and Cherry’s Proposals - Meaning has been found to be processed in the unattended message
Moray (1959) and Wood and Cowan (1995) found subjects detected their own names in the unattended ear.
Treisman (1960) found that shadowing switched ears if the semantic context of the attended message switched to the unattended ear
Treisman proposed the filter is sensitive to context and certain important words (like FIRE!) will always be considered contextually relevant and pass through the filter.
Led to the development of Late Filter Theories (Deutsch & Deutsch, 1963; Norman, 1968)
Late Filter Theories: Attention acts as a filter late in the processing stream. All sensory stimuli are analyzed for their physical characteristics and meaning, but only those that are attended to enter awareness.
Theories supported by experiments using indirect measures such as seeing if performance on a task is influenced by unattended messages.
Example: Corten & Wood (1972) conditioned GSR to an electrical shock paired with a specific word. Subjects demonstrated the GSR responses to the word even when presented in the unattended ear and the subjects had little conscious knowledge of having heard it.
© 2004 Prentice Hall

12. Late Filter Theories - Continued
Example 1: Corten & Wood (1972) conditioned GSR to an electrical shock paired with a specific word. Subjects demonstrated the GSR responses to the word even when presented in the unattended ear and the subjects had little conscious knowledge of having heard it. Some failures to replicate (Wardlaw & Kroll, 1976) but was replicated by Dawson and Schell (1982) but effect was not as robust.
Example 2: Eich (1984) – words in the unattended ear disambiguated the meaning of word homophones in the attended ear (ex. attend to fair/fare and taxi is in the unattended ear). On testing, subjects write fare. Wood, et al (1997) suggests result might be due to switching of attention from channel to channel rather than a late filter.
© 2004 Prentice Hall

13. Movable Filter Theories
Movable filter model:
An attentional model where the filter can be chosen to be early or late in the processing stream depending on needs (Posner & Snyder, 1975)
Unattended stimuli analyzed for physical characteristics
Choose to allocate attention to some material or allocate attention mostly to the material and switch periodically to the other
Supporting Experiments
Johnston & Heinz (1978) – shadowing on a semantic level interferes more than shadowing on a physical level with a secondary task. Indicates differential allocation of attentional resources
Koelsch and Tervaniemi (1999) – amount of processing may be affected by training, trained musicians demonstrated specific ERPs to unattended musical stimuli that were technically discordant.
© 2004 Prentice Hall

14. What Is Selected?
Attention seen as a spotlight before early ’80s (Norman, 1968; Posner et al, 1980) – Attention selected spatial locations
Today – attention thought to select objects and not locations
Experimental Evidence for Object Selection
If attention was spotlight, then it should take a longer time to move attention over a greater distance - NOT confirmed by Kwak et al. (1991) as seen in Fig. 3.8 in a same/different task with targets at varying distances
If attention was a beam, then as it swept from location to location it might be caught by an intervening object – NOT confirmed by Sperling & Weichselgartner (1995) in task with stimuli appearing between fixated items and attended items. The in-between stimuli did not draw attention as they would if caught in a passing attentional beam
Neisser & Becklen (1975) – attention can be successfully allocated to one of two visually superimposed video streams (two different games). Difficult to explain if attentional allocation is spatial in nature.
Baylis and Driver (1993) – more difficult to judge distances between points when they are from different objects rather than the same object (as seen in Fig 3.9). Argues for object based attention. Which vertex is higher? Examine the white parts or black parts of each illustration.
© 2004 Prentice Hall

15. What Is Selected? - Continued
Neural Evidence – O’Craven et al. (1999)
FMRI used
Subjects viewed semitransparent face superimposed over a house, with one stimulus moving
Subjects had to attend to house, face or motion
Activation was studied for specific cortical regions for separate stimulus attributes (face, place, motion)
Only the attended characteristic had its locus activated – arguing against “spotlight” or area view of attention
How Does Selection Operate? Treisman & Gelade (1980) Stimulus Arrays and Search Examples
© 2004 Prentice Hall

16. How Does Selection Operate? - Continued
Object Selection most studies by visual search – please see the illustration on slide #16 - Treisman & Gelade (1980)
Two types of searches
Disjunctive: In a visual search task, the target differs from distractors on just 1 feature (e.g., target is larger than distractors or target is only stimulus that has a horizontal line in it).
Conjunctive: In a visual search task, target differs from distractors on two features, for example, the target is large and red and although some of the distractors are large and some are red, none of the distractors are both large and red. It requires a conjunction of two features (largeness and redness) to identify the target.
On the illustration on slide #16, the left and middle are disjunctive, the right is conjunctive
Disjunctive searches are parallel in nature – all items at one time
Conjunctive searches are serial – one item at a time
© 2004 Prentice Hall

17. How Does Selection Operate? - Continued
Treisman and Gelade (1980)
Perceptual system organized into feature maps
Map contains location info for one feature (e.g. color, texture, etc.)
Contents of maps loaded preattentively
Conjunctive searches need to access two or more maps
Attention conjoins the contents of maps together
Shih and Sperling (1966)
Attention drawn to correct stimulus rather than filtering out others
Subjects had to find digit among letters. Telling them that the target would be in a slide with all large letters didn’t help.
Telling them that it would be the only small target among large characters did
Conclusion: Critical feature can draw attention but it cannot filter out incorrect stimuli.
© 2004 Prentice Hall

18. Why Does Selection Fail?
Assumed Order of Sensory Processing
Processing Physical Characteristics ↓
Processing Semantics ↓
Awareness
Early Filters – located right after sensory processing
Late Filters – located right after semantic processing
Properties of Attention that Cause Selection Failure
Interaction of Attention with other Components of Cognition
© 2004 Prentice Hall

19. Properties of Attention that Cause Selection Failure
Inhibition of Return:
If attention focuses on an object and then moves to another object, it is difficult to return attention to that object for several seconds.
First described by Posner (1978; Posner and Cohen, 1984) – warning signal interferes with response to target at same location
Tipper, et al. (1991) – Inhibition of Return based on objects and not location
Theorized that IOR makes search more efficient as there would be a bias not to return to an already inspected item
© 2004 Prentice Hall

20. Properties of Attention that Cause Selection Failure - Continued
Ironic Processes of Mental Control:
Attending to something you don’t want to (Wegner, et al. 1987)
Two processes of mental control
Operating process – seeks mental contents consistent with what you want to think about
Monitoring process – searches for processes that are inconsistent
Operating process demands attention, Monitoring does not
If resources are scare, the Operating process cannot bring consistent contents to awareness and the Monitoring processes brings inconsistent thoughts to alert the system that they are present.
© 2004 Prentice Hall

21. Properties of Attention that Cause Selection Failure - Continued
Maintaining Attention: Vigilance
The ability to maintain attention to a task in which stimuli appear infrequently
Can be analyzed in terms of Signal Detection Theory’s two factors
Sensitivity – absolute ability to detect
Bias – whether you use a liberal or conservative criterion for reporting a detection
Sensitivity decreases can be due to boredom, habituation, decline in motivation
Sensitivity declines also depend on task – Parasuraman and Davies suggest sensitivity drops only for tasks with high event rates
Koelega, et al. (1989) suggests sensitivity drops for sensory task but is stable for cognitive tasks
See, et al. (1995) – with sensory tasks, sensitivity gets worse for simultaneous tasks and better for successive task, vice versa for cognitive tasks
© 2004 Prentice Hall

22. Interaction of Attention with other Components of Cognition
Structural Explanation – Interference between two task is caused by competition for mental structures, not attentional resources
Two effects of interest
Psychological Refractory Period (Welford, 1952; Pasher, 1998): A period of time after one response is executed during which a second response cannot be selected. Reflects a bottleneck in response selection as seen in Figure 3.12
Attentional Blink: In a rapid serial visual presentation (RSVP) as seen in Fig. 3.13, observers have trouble identifying the second target if it appears anywhere between 100 to 600 ms after the first target. Seems to represent a central bottleneck but not one of attention
© 2004 Prentice Hall

23. Automaticity and the Brain
Do regions of the brain or processes differ when a task becomes automatic?
Jansma, et al. (2001) – with a working memory task found no difference in dorsolateral prefrontal cortex, right superior frontal cortex and supplementary motor cortex
Jueptner et al. (1997) with a sequenced motor task found:
Early learning associated with dorsal prefrontal cortex and anterior cingulate cortex
Automatic performance with posterior parietal cortex
Thinking about movements activated dorsal prefrontal and anterior cingulate cortices
There may be more than one brain mechanism for automaticity.
© 2004 Prentice Hall