Perceptual Processes: Attention & Consciousness

1. Perceptual Processes:Attention & Consciousness Dr. Claudia J. Stanny EXP 4507 Memory & Cognition Spring 2009

2. What do we mean when we say we are “paying attention?” • Focus on one task to exclusion of others • Selectivity • Inhibition of irrelevant information • Ability to shift attention (disengage from one task and engage with another task) • Maintaining focus • Vigilance – sustained attention to one task • Division of effort across multiple tasks • Multitasking • Allocation of resources to multiple tasks Claudia J. Stanny

3. Defining Attention • Vigilance (Sustained attention) • Selective Attention (Focus on one task) • Division of Attention (Multitasking) • Attention as processing capacity or mental effort • Controlled Processing (Attentional Processing) • Automatic Processing Claudia J. Stanny

4. Vigilance • Sustained attention • Example: Radar screen operators • Problems with boredom and distractibility • Lapses • Missed signals • Observers periodically disengage from tasks to monitor the environment • Neurological aspects of periodicities in attention (Aue, Arruda, Kass, & Stanny in review) Claudia J. Stanny

5. Selective Attention Tasks • Ability to focus attention • Dichotic Listening Task • Shadowing Task • Stroop Task • Selection of one stimulus source, task, or response • Inhibition of other stimulus sources, tasks, or responses Claudia J. Stanny

6. Selective Attention: Shadowing Tasks • Cocktail Party Phenomenon • Two distinct messages arrive at each ear • Task is to repeat (shadow) the message in one ear Claudia J. Stanny

7. Selective Attention: Dichotic Listening Tasks • Two sets of digits • Report by time of arrival • Report by location (left ear, right ear) • Relative cost of reporting by location or switching channels to report by time of arrival Claudia J. Stanny

8. Selective Attention: Dichotic Listening Tasks • Sometimes the cost of switching from one channel to another is less than predicted by an early selection model Claudia J. Stanny

9. Stroop Task • Stimulus activates competing responses • Color name (generated by reading) • Color name (generated by perception of color) • Two possible task demands: • Read the word • Name the ink color • Must inhibit one response to make the correct response for the task demands Claudia J. Stanny

10. Demonstration of the Stroop Task Claudia J. Stanny

11. Divided Attention • Division of attention across multiple tasks • Questions: • To what extent can attention be divided without loss in quality of performance on tasks? • To what extent does practice change our ability to maintain task performance when attention is divided? Claudia J. Stanny

12. What is the effect of practice?Automatic & Controlled Processing • Schneider & Shiffrin, 1977; Shiffrin & Schneider, 1977 • Controlled Processing • Attentional processing • Sequential, slow, flexible, requires resources • Bottlenecks likely to occur during multi-tasking • Automatic Processing • Distributed processing • Parallel, fast, inflexible, requires few resources • May be able to multi-task automatic processes Claudia J. Stanny

13. Demonstration of Automatic and Controlled Processing in the Shiffrin & Schneider Task Claudia J. Stanny

14. Theories of Attention • Bottleneck theories • Resource theories • Feature integration theory Claudia J. Stanny

15. Bottleneck Theories • Where in the stream of information processing does the bottleneck (selectivity) occur? • Filter Theory (Broadbent, 1958) • Attenuation Theory (Treisman, 1960) • Late Selection Theory (Deutsch & Deutsch, 1963) Claudia J. Stanny

16. Attention as Processing Resource • Attention as an allocation of capacity or resources for processing information • Kahneman (1973) Attention and Effort • Role of arousal • Effects of practice • Potential for multitasking Claudia J. Stanny

17. Implications for Multitasking • Development of automaticity can reduce demands on processing resource • Automatic processing can enable the division of attention and multitasking • Possible for simple, highly practiced tasks • Errors appear when one or more tasks become more demanding Claudia J. Stanny

18. Costs of Automaticity • Costs of rapid switching between tasks • Task analysis : Evaluate the specific demands of each task • Automatic processes are inflexible and lead to errors when situation requires a new response • Example in the Schneider & Shiffrin task: Attentional Capture • Example in the Stroop task: Difficulty in inhibiting rapid but irrelevant responses Claudia J. Stanny

19. Multitasking Application: Driving while talking on a cell phone Cole, Kass, & Stanny (2007) Claudia J. Stanny

20. Consequences of Divided Attention:Other Applications • Response times are slower when we are engaged in a cell phone conversation • Distracting effects of advertising on web pages • Web pages with ads take longer to read and comprehend than those without ads • Added effects of animated ads • Memory and understanding of main points in text is worse when textbooks include irrelevant cartoons and side bars to generate interest • Relevant photos, cartoons, and other materials aid learning; irrelevant materials just distract Claudia J. Stanny

21. Visual Search • Feature present searches • Target identified by a single feature • Rapid, parallel searches (target “pops out”) • Feature absent searches • Target identified by the absence of a single feature • Slow, serial examination of each stimulus • We process positive information (feature present) more rapidly than negative information (feature absent) Claudia J. Stanny

22. Demonstration:Visual Search Tasks Claudia J. Stanny

23. Conjunction Searches • Target is a combination of features • Non-targets have only one of the features • Slow, serial search process • Focused attention to a location required to detect integrations of features • When attention is distracted, illusory combinations of features might occur Claudia J. Stanny

24. Demonstration: Searches involvingFeature Conjunctions Claudia J. Stanny

25. Feature Integration TheoryTreisman & Gelade (1980) • Distributed attention • Process stimuli in parallel • Processing is distributed across the spatial array • Process dominated by feature detection • Focused attention • Process stimuli serially • Attention is allocated to a specific spatial location to accurately integrate the features for that stimulus Claudia J. Stanny

26. Neurological Correlates of Attention • Orienting attention network • Parietal lobe; active during visual search tasks & when attending to spatial locations • Visual neglect when this area is damaged • Executive attention network • Frontal lobe; inhibits automatic responses when task produces conflicting responses (e.g., Stroop) • Top-down control of attention • Alerting attention network • Orienting responses to novel stimuli Claudia J. Stanny

27. Unilateral Neglect • Lesions of posterior parietal lobe • Some role of frontal lobe • Hemineglect • Usually seen with right parietal lesions Claudia J. Stanny

28. Visual Search in Unilateral Neglect Visual search strategies are biased to one side of the visual field in neglect Severity of neglect is exaggerated with increased visual clutter Husain, M (2008). Scholarpedia, 3(2):3681. Claudia J. Stanny

29. Attention and Consciousness • Role of subjective awareness • Awareness of products of mental processing • Level of awareness of mental processes themselves • Rapidity of some processes (e.g., retrieval) make them inaccessible to awareness or conscious examination • Role of self-report as valid data about some processes (e.g., problem solving, metamemory, metacognition) Claudia J. Stanny

30. Disorders of Attention • Obsessive-Compulsive Disorder • Attentional Deficit Disorder • Blindsight • Damage to visual cortex, sub-cortical visual areas intact Claudia J. Stanny