1. Psych 435Attention

2. Issues • Capacity • We can’t respond to everything in the environment • Too many pieces of information • we can only actively respond to a subset of these • Attention • The selection of relevant cues to respond to • Cues may be externally or internally generated

3. Attention • What is attention? • “The concentration of mental effort on sensory or mental events” • Phenomena • Switching vs. sharing attention • Attention Capture • Visual Search • Selective attention- Stroop

4. Examples of Controlled vs. Automatic Processes • Show 3 pairs of search demos • Each member of each pair will have a few or a lot of items • Search for a single target

6. Find the T: L L T L L L L L

8. This was an automatic process: fast

10. Find the T: L L L L L L L L L L L T L L L L L L L L L L L L L L L L L L L L L L

12. This was an automatic process: still fast even with more distractors

14. Find the T: L T L L L L L

16. Slower without color

18. Find the T: L L L L L L L L L L L L L L L L L L L L L L L L L L T L L L L L L L

20. This was a controlled search- slower, look at each letter • Much slower than with colored T

22. Find the Red L T L T T T T L L L L

24. Slow: searching for a conjunction

26. Find the Red L T L T T L L L L L L L T L L T L L T T T T L L T T L L L T T L L L T L L T L L L T L L T L T L T L L L L L T T

28. Even slower- searching for a conjunction

29. Data from Display Set-Size Experiment • Fast search done with automatic (preattentive) mechanisms • Done in parallel • Slow search done with controlled (attentive) mechanisms • Done in serial

30. Applications of Attentional Seach • List search situations and decide if fall into preattentive or attentive search requiring focal attention • E.g. • Search computer screen for icon • scan crowd for people • scan crowd for americans • look for airplane in sky • What makes things preattentive? • probably the amount of difference between the objects • L’s and T’s are similar • Red and blue are quite different • Looking for small differences requires focal attention

31. Models of attention • Filter Models • Recognition after Filtering • Broadbent -or- • Recognition before Filtering • Broadbent’s critics • Attentuation Models • Treisman • Automatic vs. Controlled Processes • Also called Preattentive vs. Attentive Processes. • Neisser • Schneider and Shiffrin

32. Filter Models • What is a Filter? • A description of the response properties of the system • Describes what a system responds to, and what it doesn’t respond to.

33. Types of Filter Models Detection Recognition Input Recognition After Filtering (Broadbent): Filter Input Detection Recognition Recognition Before Filtering: Filter Input Detection Recognition

34. Broadbent’s Filter Model • Channels carry different types of information • E.g. color, spatial frequency, pitch, hot, etc. • Apply mental effort: selectively process info coming from a small set of channels • We must do this: limited capacity processing and memory system • We just can’t deal with all the information at once • However, can switch between channels

35. Broadbent’s Filter Model cont. • On the basis of some aspect of the stimulus or our memories, we can switch between channels • This switching may be voluntary or involuntary • Switching takes effort, reduces performance • Broadbent’s dichotic listening techinque- present two digits at once, one to each ear • 8, 3, 2 in left ear • 9, 1, 5 in right ear • recall by ear (left or right): subjects respond “8 3 2 9 1 5” • or in order: subjects respond “8 9 3 1 2 5” • performance for latter task is reduced (65% to 20%) • In second task subjects had to switch more often- hurts.

36. Broadbent’s Filter Model cont. • Problems: Gray and Wedderburn (1960) • Easy to switch if information in the to-be-switched-to ear is relevant • e.g.: Story continues in alternating ears • Problems: GSR experiments • Associate word with shock- hearing word elicits a GSR response. • When that word is presented in unattended channel, produces GSR response. • Semantically similar words also elicit response- some semantic processing takes place in unattended channel.

37. Attenuation Models-Treisman • Info in unattended channels is still processed • but at a reduced rate • info in unattended channels is attenuated.

38. Treisman’s Attention Model

39. Attention Capture

40. Failures of Selective Attention • Attention is supposed to focus in on what you want to attend to • Exclude irrelevant information

41. Stroop Task Blue Yellow Red Green Green Yellow Green Yellow Yellow Green Blue Blue Red Blue Red Green

43. Stroop Task ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** *****

45. Stroop Task Blue Yellow Red Green Green Yellow Green Yellow Yellow Green Blue Blue Red Blue Red Green

46. Stroop Task Yellow Green Blue Yellow Blue Blue Red Green Red Red Yellow Red Blue Yellow Blue Blue

47. Stroop • Failure of selective attention • Race model • Word name is processed automatically • Color is not so automatic • Both arrive at the same time, we have a hard time attending to the relevant stimulus attribute • Doesn’t happen upside down

48. Stroop Task

49. Failure of Attention: Failure to Disengage • Mind Develops Brain clip • infant- failure to disengage

50. Spatial Attention: Posner Task Fixation Point Cue 75% accurate T i m e Attention switches to here (but eyes don’t move) or here: A A Target might appear here: