Attention

1. Attention What is it? What control do We have over it? cogch3 Attention

2. Everyone knows what attention is. It is the taking of possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence….. It implies withdrawal from some things in order to deal more effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state which …. Is called distraction. - William James (1890) cogch3 Attention

3. Read the bold print. Somewhere Among hidden the in most the spectacular Rocky Mountains cognitive near abilities Central City is Colorado the an ability old to miner select hid one a mes sage box from of another. gold. We Although do several this hundred by people focusing have our looked attention for on it, certain they cues have such not as found type it style. What do you remember from the regular print text? What does this tell you about selective attention? cogch3 Attention

4. Focused or Selective Attention Task: Present people with two or more stimulus at the same time and instruct them to respond to only one. cogch3 Attention

5. Attention Perceptual processes - Parallel & Unlimited Attention - Serial and Limited At some point there is a bottleneck. cogch3 Attention

6. We need to select which input will be attended to (and further processed) and which will be ignored (and lost). Questions 1) Is bottleneck before or after meaning has been processed? 2) How do we select what to attend to? cogch3 Attention

7. Dichotic Listening Task (Cherry, 1953) - two messages presented Shadowing task - repeat message presented in one ear as you are hearing it. Dependant Measures 1) Shadowing performance (errors, hesitations, omissions) indicate that attention has been diverted. 2) What is recalled from the unattended message? cogch3 Attention

8. Dichotic Listening Task cogch3 Attention

9. Dichotic Listening Results Physical attributes of unattended channel are detected (e.g., Male . vs. female voice; Human vs. musical instruments). Semantic (meaning) attributes of unattended channel were missed (e.g., Don’t notice switch to foreign language). No content was remembered, even when the unattended stream was the same word presented 35 times (Moray, 1959). cogch3 Attention

10. Broadbent’s Early Filter Model • An early-selection model - filtering occurs before incoming stimuli are analyzed to the semantic level cogch3 Attention

11. Parts of the filter model • Sensory store - Holds incoming information for a short period of time • Filter - Analyzes messages based on physical characteristics like tone of voice, pitch, location of stimulus (which ear) • Detector - Information is processed to determine meaning • Short-term memory - Holds information for general processing cogch3 Attention

12. :-) H M :-) R S :-) W P Broadbent’s Split-Scan Study • Present letters at the same time to each ear cogch3 Attention

13. :-) H M :-) R S :-) W P Broadbent’s Split-Scan Study • Two conditions: 1.) Repeat back all letters in any order 2.) Repeat back letters in the order they were presented Condition 1 (Any Order): H, R, W, M, S, P Condition 2 (In Order): H, M… P? cogch3 Attention

14. Split-Scan Results • Condition 1 (repeat back in any order) • 65% correct letter report • Would report all letters presented to one ear first • Condition 2 (repeat back in presented order) • 20% correct letter report • Suggests that the letters to one ear were stored briefly while those of the other ear were processed. cogch3 Attention

15. The early filter model explains… • How we can pay attention to one ear and ignore stimuli coming into the other ear • Why we prefer to process stimuli that come in to one ear all at once as opposed to switching channels cogch3 Attention

16. Problems with early filter model Back at the cocktail party. You’re talking to your friend and ignoring all the other conversations… Until someone across the room says your name. Then you turn your head. But you were supposed to be ignoring other conversations - what happened? cogch3 Attention

17. Moray (1959) - “cocktail party effect” subjects could often detect their own name “fire” or context relevant words on unattended channel. How could this happen if unattended information does not pass through filter for pattern recognition? cogch3 Attention

18. Late selection models Deutsch & Deutsch, 1963) information is selected after meaning has been processed. cogch3 Attention

19. Evidence against: (Treisman & Riley, 1969) • Used shadowing task asked subject to indicate when they detected a target in either message. Many more targets were detected on the shadowed message. cogch3 Attention

20. Corteen & Wood (1972): Experiment in which subjects were first given mild shocks whenever certain words--city names--were presented in a long list. This set up a conditioned autonomic response, the galvanic skin response or GSR, which measures changes in the resistance of the skin with sweating. After training, just seeing the city name increased GSR. Then Ss SHADOWED prose in one ear and heard a list of words in the other. The list included the city names plus new city names, and neutral words. Measured GSR. cogch3 Attention

21. Coch et al., (2005) same task as Treisman 1969 except ERPs were recorded to determine if target words were being processed. ERPs 100ms after target presentation (indication that the target has been perceived) were greater for targets in the attended compared to the unattended message. cogch3 Attention

22. Treisman (1960) Found that attention could be easily switched to the unattended ear when semantic content of the message shifted cogch3 Attention

23. Treisman’s attenuation model • Still an early-selection theory • Instead of a filter, an attenuator analyzes incoming messages • Physical characteristics • Language - Groups of syllables/words • Attended messages are given more priority cogch3 Attention

24. Attenuation = loss of signal strength cogch3 Attention

25. The Dictionary Unit • Both messages gets passed on to the dictionary unit Threshold = Smallest signal strength that can just be detected Easily detected cogch3 Attention

26. Attenuation explains… • Hearing your own name when that stream is supposed to be ignored • Switching channels in order to make a complete sentence • But a specific dictionary unit? That seems like a cop-out. cogch3 Attention

27. Problems with early selection • MacKay (1973) • Ambiguous sentences: “They were throwing stones at the bank” • Bank = Financial institution or side of a river? cogch3 Attention

28. MacKay Method & Results • Dichotic listening • Attended stream: Ambiguous sentence • “They were throwing stones at the bank.” • Unattended stream: Biasing word • “River” or “Money” • The biasing word had an effect! • If “money”, the ambiguous sentence was more likely interpreted as financial institution cogch3 Attention

29. What does this mean? • The unattended stream was being processed, and it wasn’t a name or another low-threshold word • Not early-selection • Not an attenuator • The word was actually being processed to the semantic level (to its meaning) cogch3 Attention

30. So what’s right? • There’s evidence for EVERYTHING! • That’s no good. • Lavie (1995) - Where the filtering occurs depends on task load • How much of a person’s cognitive resources are used in a task cogch3 Attention

31. Perceptual Load Theory:The location of the filter is Flexible • High-load task: Difficult, requiring most of someone’s cognitive resources • Only selected items are processed • Low-load task: Easier, cognitive resources are left over • Can process additional information cogch3 Attention

32. Johnston & Heinz (1978) Multimode attention theory:Selective attention can operate anywhere, early or late, but the later it operates the more costly in terms of resources (mental effort) it isDemonstrated this using a task which showed that processing difficulty increased as the lateness of attention selection increased cogch3 Attention

33. Dual Task Procedure • Dichotic listening with shadowing Independent Variables:   messages physically differ (different sex Speakers or do not (same sex speakers). 2) Detect light stimuli on a computer screen. Dependent Measure:   time to respond to presence of lightResults:  Early (physical) differences created much less slow down than Late (semantic) differences. cogch3 Attention

34. More than 2 messages (created so they appear to come from different sources), does not increase response times. Processing unattended message does not take resources, selecting it does. cogch3 Attention

35. Summary 1. Filter is flexible - depends on the task • Later selection takes more effort. • Effort depends on selection not on amount of background. cogch3 Attention

36. Selective Visual Attention cogch3 Attention

37. Spot Light/Zoom Lens Metaphor • Can be directed to specific areas • Can be diffuse or focused - trade off in concentration • Concentrated at the center, fuzzy at the borders • Limited capacity cogch3 Attention

38. Muller et al., 2003 Zoom Lens Theory predicts that if you are focusing on two items, your attention should also be good for any item that falls between the two items. Evidence show that if attention is split between two cued locations, detections of items falling between is poor. cogch3 Attention

39. Figure 3.1 (a) Shaded areas indicate the cued locations and the near and far locations are not cued. (b) Probability of target detection at valid (left or right) and invalid (near or far) locations. Based on information in Awh and Pashler (2000).

40. When attention is split, it can act like multiple spot lights. With unattended areas falling in spaces between attended areas. cogch3 Attention

41. What Happens to Unattended Stimuli? Evidence from Neglect Patients. Shown some pictures to the non-neglected visual field and others to the neglected visual field. Later asked to identify the same pictures in a degraded version. They are just as fast with those that had been presented to the neglected as the non-neglected visual field (priming). cogch3 Attention

42. Neurological evidence also indicates that when the overall attentional load of a task was low, neglect patients showed increased brain activity to task irrelevant items presented in the neglected visual field (some processing is going on) even though the patients are not consciously aware of the stimuli. cogch3 Attention

43. Hemi neglect Patients Suffering From 'Hemi -neglect' Ignore Things On Their Left, But They See Them Nonetheless Click here to see Science Daily article (05/15/08.) This study demonstrates that in hemi-neglect the left part of the world is not a 'blind' region: in a way, patients read unconsciously what is there. However, the patients cannot make conscious use of this information cogch3 Attention

44. Attention as Capacity • Attention is the process of allocating mental resources to various cognitive tasks Factors effecting allocation of Attention • Anxiety • Salience and Distinctiveness • Relevance • Task demands cogch3 Attention

45. Cross- Modality Effects Ventriloquist Illusion Rubber Hand Illusion Phantom Limb Pain (begin at 13:00) Body Swap Illusion cogch3 Attention

46. Disorders of Visual Attention Hemi-neglect – (Historical note) President Woodrow Wilson after suffering two strokes developed hemi neglect. When colleagues came to visit him, he failed to respond to them until they were escorted to his right side. He denied he had a problem and planned to run for a third term as president until his wife finally intervened. cogch3 Attention

47. Spatial Extinction: can detect a single item in both the left and right visual fields but, under conditions double simultaneous stimulation fail to detect the item in the left field. Presented Perceived cogch3 Attention

48. When stimuli is presented in the neglected field but has no competition for attention from the non-neglected visual field, the image is perceived. When there is competition for attention from the non-neglected visual field, attention is given only to the non-neglected visual field. cogch3 Attention

49. Two Attention Systems (Corbetta) Goal directed system -  preparing and applying goal-directed (top-down) selection for stimuli and responses. Effected by expectations, knowledge and/or intentions. Stimulus driven – (bottom-up) specialized for the detection of behaviorally relevant stimuli, particularly when they are salient or unexpected. Circuit breaker . cogch3 Attention

50. The area were the two attention systems combine is in the parietal lobe. There is competition for attention from the two attentional systems. Hemi- neglect can occur due to impairment in either the goal-directed or the stimulus driven systems. Results in a failure to activate the parietal cortex enough to capture attention to that visual filed. Hemi-neglect is a disorder of Attention – not of perception. cogch3 Attention