Chapter 4

1. Chapter 4 Attention

2. Some Questions to Consider • Is it possible to focus attention on just one thing, even when lots of other things are going on at the same time? • Under what conditions can we pay attention to more than one thing at a time? • What does attention research tell us about the effect of talking on cell phones while driving a car? • Is it true that we are not paying attention to a large fraction of the things happening in our environment?

3. Attention • Process of concentrating on specific features of the environment or on certain thoughts or activities • Selective: excluding of other features of the environment • Limited: in capacity and timing • Both overt and covert: we can consciously attend to information but some information grabs our attention

4. Selective Attention • Ability to focus on one message and ignore all others • We do not attend to a large fraction of the information in the environment • Filtering out some information and promoting other information for further processing

5. Research Method: Dichotic Listening • One message is presented to the left ear and another to the right ear • Participant “shadows” one message to ensure he is attending to that message • Can we completely filter out the message to the unattended ear and attend only to the shadowed message?

6. Caption: In the shadowing procedure, a person repeats out loud words he has just heard.

7. Results of Dichotic Listening • Participants could not report the content of the message in unattended ear • Knew that there was a message • Knew the gender of the speaker • However unattended ear is being processed at some level • Cocktail party effect • Change in gender is noticed • Change to a tone is noticed

8. 0 Models of Selective Attention • Where does the attention filter occur? • Early in processing • Later in processing • Early selection model • Broadbent’s filter model • Intermediate selection model • Tresiman’s attenuation theory • Late selection model • e.g. McKay (1973)

9. Broadbent’s Filter Model • Early-selection model • Filters message before incoming information is analyzed for meaning Caption: Flow diagram of Broadbent’s filter model of attention.

10. Broadbent’s Filter Model • Sensory memory • Holds all incoming information for a fraction of a second • Transfers all information to next stage

11. Broadbent’s Filter Model • Filter • Identifies attended message based on physical characteristics • Only attended message is passed on to the next stage • Detector • Processes all information to determine higher-level characteristics of the message

12. Broadbent’s Filter Model • Short-term memory • Receives output of detector • Holds information for 10-15 seconds and may transfer it to long-term memory

13. 0 Broadbent’s Model Could Not Explain • Participant’s name gets through • Cocktail party phenomenon • Participants can shadow meaningful messages that switch from one ear to another • Dear Aunt Jane (Gray & Weddeburn, 1960) • Effects of practice on detecting information in unattended ear • You can be trained to detect in unattended ear • Based on the meaning of the message

14. Tresiman’s Attenuation Theory • Intermediate-selection model • Attended message can be separated from unattended message early in the information-processing system • Selection can also occur later Caption: Flow diagram for Treisman’s attenuation model of selective attention.

15. Treisman’s Attenuation Theory • Attenuator • Analyzes incoming message in terms of physical characteristics, language, and meaning • Attended to message is let through the attenuator at full strength • Unattended message is let through at a much weaker strength

16. Treisman’s Attenuation Theory • Dictionary unit • Contains words, each of which have thresholds for being activated • Words that are common or important have low thresholds • Uncommon words have high thresholds

17. Caption: The dictionary unit of Treisman’s model contains words, each of which has a threshold for being detected. This graph shows the thresholds that might exist for three words. The person’s name has a low threshold, so it will be easily detected. The thresholds for the words rutabaga and boat are higher, because they are used less or are less important to this particular listener.

18. Late Selection Models • Selection of stimuli for final processing does not occur until after information has been analyzed for meaning

19. Late Selection Models • McKay (1973) • In attending ear, participants heard ambiguous sentences • “They were throwing stones at the bank.” • In unattended ear, participants heard either • “river” • “money”

20. Late Selection Models • McKay (1973) • In test, participants had to choose which was closest to the meaning of attended to message: • They threw stones toward the side of the river yesterday • They threw stones at the savings and loan association yesterday

21. Late Selection Models • McKay (1973) • The meaning of the biasing word affected participants’ choice • Participants were unaware of the presentation of the biasing words

22. Task Load and Selective Attention? • Task load: how much of a person’s cognitive resources are used to accomplish a task • High-load: uses almost all; no resources for other tasks • Low-load: uses few; resources for other tasks

23. Caption: Flanker-compatibility task. (a) Display in which the small square is the target, and the large square on the right is the distractor. This distractor is “compatible” because it is the same as the target. (b) Display in which the distractor is “incompatible” because it is different from the target. (c) Results of Green and Bevelier’s (2003) experiment, which found that the reaction time to indicate the presence of a target is longer for the incompatible distractor (bar I) than for the compatible distractor (bar C).

24. Flanker-Compatibility Task • Can participants focus their attention on detecting the target so that the identity of the distractor will not affect their performance?

25. Flanker-Compatibility Task • Low-load condition: one potential target • Reaction time is longer for incompatible distractors • Participant still had resources available to process additional information

26. Caption: Stimuli for the flanker-compatibility task in which the load is increased by adding additional stimuli to the display. The target is still the square, as in figure 4.10, so the distractor is compatible in (a) and incompatible in (b). The results, shown in (c), indicate that under this high-load condition, the reaction times are the same for both compatible and incompatible distractors. (From Green & Bevelier, 2003).

27. Flanker-Compatibility Task • High-load condition: type of distractor does not affect reaction time • Participants use all resources • No resources to process the distractor

28. Video-Game Experts • Low load: experts’ performance is similar to non-experts • High load: experts still had enough resources left to process distractors • Performance transferable to flanker-compatibility task

29. Effect of Load on Selective Attention • High-load experiments support early selection • Low-load experiments support late selection

30. Divided Attention • Practice enables people to simultaneously do two things that were difficult at first • Spelke et al. (1976) • After hours of practice, participants could read and categorize dictated words

31. Divided Attention • Schneider and Shiffrin (1977) • Divide attention between remembering target and monitoring rapidly presented stimuli • Memory set: 1-4 target characters • Test frames: could contain random dot patterns, a target, distractors

32. Caption: Consistent mapping condition for Schneider and Shiffrin’s (1977) experiment.

33. Caption: Improvement in performance with practice in Schneider and Schiffrin’s (1977) experiment. The arrow indicates the point at which participants reported that the task had become automatic. This is the result of experiments in which there were four target stimuli in the memory set and two stimuli in each frame.

34. Divided Attention • Consistent mapping condition: target would be numbers, and distractors would be letters • Over time, participants became able to divide their attention • Automatic processing occurs without intention and only uses some of a person’s cognitive resources

35. Divided Attention • Stroop effect • Name of the word interferes with the ability to name the ink color • Cannot avoid paying attention to the meanings of the words

36. Caption: Varied mapping condition for Schneider and Shiffrin’s (1977) experiment. This is more difficult than the consistent mapping condition because all the characters are letters and also because a character that was a distractor on one trial (like the T) can become a target on another trial, and a character that was in the memory set on one trial (like the P) can become a distractor on another trial.

37. Divided Attention • Schneider and Shiffrin (1977) • Varied mapping condition: rules changed from trial to trail • Over time, participants never achieved automatic processing

38. Divided Attention • Controlled processing: participants paid close attention, and their search was slow and controlled

39. Caption: Comparing performance on the consistent and varied mapping tasks. Note that the horizontal axis indicates the duration of each target frame. These graphs show that frames must be presented for longer durations to achieve good performance in the varied mapping condition.

40. Divided Attention • 100-car naturalistic driving study • Video recorders placed in cars • Risk of accident is four times higher when using a cell phone

41. Divided Attention • Strayer and Johnston (2001) • Simulated driving task • Participants on cell phone missed twice as many red lights and took longer to apply the brakes • Same result using “hands-free” cell phone

42. Attention and Visual Perception • Inattentional blindness: a stimulus that is not attended is not perceived, even though a person might be looking directly at it

43. Caption: Inattentional blindness experiment. (a) On each trial, participants judge whether the horizontal or vertical arm is longer. (b) After a few trials, the inattention trial occurs, in which a geometric object is flashed along with the arms. (c) In the recognition test, the participant is asked to indicate which geometric object was presented.

44. Attention and Visual Perception • Change blindness: if shown two versions of a picture, differences between them are not immediately apparent • Task to identify differences requires concentrated attention and search

45. Caption: Frames from the video shown in the Levin and Simons’ (1997) experiment. Note that the woman on the right is wearing a scarf around her neck in shots A, C, and D, but not in shot B. Also, the color of the plates changes from red in the first three frames to white in frame D, and the hand position of the woman on the left changes between shots C and D.

46. Overt Attention • Eye movements, attention, and perception • Saccades: rapid movements of the eyes from one place to another • Fixations: short pauses on points of interest • Studied by using an eye tracker

47. Bottom-up Determinants of Eye Movement • Stimulus salience: areas that stand out and capture attention • Bottom-up process • Depends on characteristics of the stimulus • Color and motion are highly salient

48. Top-Down Determinants of Eye Movements • Scene schema: knowledge about what is contained in typical scenes • Help guide fixations from one area of a scene to another • Eyes movements are determined by task • Eyes movements preceded motor actions by a fraction of a second

49. Caption: Sequence of fixations of a person making a peanut butter sandwich. The first fixation is on the loaf of bread.

50. Covert Attention: Attention without Eye Movements • Precueing: directing attention without moving the eyes • Participants respond faster to a light at an expected location than at an unexpected location • Even when eyes kept fixed