1. Attention What is attention?
Our everyday use of the word attention (e.g., pay attention to the costs of the politicians’ promises) implies
Selection of some information for further processing

2. Attention
Definition
attention is the taking possession by the mind, in clear and vivid form, of one of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence.
William James (1890) Principles of Psychology

3. Attention Types of attention why is attention important selective
sustained attention/vigilance
divided
why is attention important
selective: people are limited in their capacity to process incoming information; therefore need to be able to focus on information that is relevant to their goals

4. Attention sustained: necessary in order maintain goal orientation
divided: frequently, it is functional to process two different streams of information

5. Attention Selective attention
Selective attention can be selective in space; processing information in one location may cause you to miss other information
Selective attention can be selective in time; when new information is rapidly and serially presented, processing some of that information may cause you to miss other information

6. Attention Selective attention Power of selective attention
Simon & Levins (1998)
Experimenter stopped pedestrian and asked for directions; during conversation 2 people with a door walked between experimenter and pedestrian
2nd experimenter then continued conversation

7. Attention Selective attention
Only half the participants noticed change in experimenter (speaker) even when asked
Phenomenon is called change blindness
Change blindness refers to a failure to detect a change in the environment

8. Attention Is selective attention important in everyday life?
Other examples
In movie Pretty Woman there was change from a croissant to a pancake that few people noticed
In change studies this finding has been replicated both in visual modalities (change blindness) and auditory modalities (change deafness)
Google Change blindness for examples

9. Attention Selective attention
Change blindness indicates that we process only a fraction of info in our environment
studies have shown that people are more likely to attend to and process information of ‘central interest’ than information of ‘marginal interest’
Thus attention appears to be guided by ‘top-down’ processing – goals of participant; thematic content of scene, etc.

10. Attention Selective attention
Change blindness indicates that we process only a fraction of info in our environment
studies have shown that people are more likely to attend to and process information of ‘central interest’ than information of ‘marginal interest’
Thus attention appears to be guided by ‘top-down’ processing – goals of participant; thematic content of scene, etc.

11. Attention Selective attention
Is attention always selective and voluntary?
Evidence suggests that a salient, external stimulus (e.g., sound of broken glass, bright light) may drive attention; called exogenous attention
Attention is said to be automatically activated
Endogenous attention is a form of covert attention that is internally controlled (e.g., looking for a gas station when driving); it is driven by goals

12. Automaticity When is a skill automatic? Posner and Snyder (1975)
it occurs without intention
it does not give rise to conscious awareness
it does not interfere with other mental activities
Stroop effect demonstration
in this demonstration I want you to name the ink colours of the words as rapidly as possible

13. Automaticity red yellow blue red green red yellow green
blue green red yellow
red green red yellow

14. Automaticity red yellow blue red green red yellow green
blue green red yellow
red green red yellow

15. Automaticity Stroop (1935) effect
most people cannot avoid reading the words; thus, it would appear that reading words occurs automatically without intent

16. Automaticity Automaticity
some tasks always appear to be performed automatically
however, other tasks become automatic only after extended levels of practice

17. Automaticity Automaticity
Shiffrin & Schneider (1977) investigated the effects of practice on memory search task
study: present small list of items to remember (letters or numbers)
test : present single item; participant indicates as rapidly as possible whether item was part of study list
Results: RT increases with study list size; however, with practice using a single list of items RT becomes flat

18. Automaticity Automaticity
Logan (1998) has proposed that as a task becomes practiced, the correct outcome becomes represented in memory, and that rather than using a rule or a procedure to obtain the outcome, the task cues the memory and the outcome is retrieved and produced

19. Neuropsychology of attention
Corbetta et al. (1991)
used PET to show that when a person attends to the movement of a stimulus (through instruction) the brain regions known to be associated with the processing of movement information show increased activity
alternatively, when a person attends to the colour of the same moving object, the colour-processing areas show increased activity

20. Neuropsychology of attention
Thus, attention appears to amplify or enhance the signals corresponding to that aspect of the stimulus to which the person is attending
Posner has proposed that there are three separable aspects of attention
arousal: found in subcortical areas of the brain
spatial attention (posterior attention): based in the parietal lobes
sustained attention (anterior attention): based in the frontal lobes

21. Attention Selective attention–selection failures in time
Shapiro (1984) how rapidly information can be processed by presenting a sequence of letters one at a time rapidly (15 ms) with 90 ms interval between letters
One of the letters, T1, was presented in white, while the remaining letters were presented in black
Second letter, the probe (T2) was presented at varying intervals following T1

22. Attention Selective attention– failures of selection in time
Insert Figure 3-4 a here

23. Attention Selective attention– failures of selection in time
Single-task condition -- report whether probe letter (T2) had been presented and ignore T1
Dual-task condition – report whether T2 had been presented and identify T1

24. Attention Selective attention– failures of selection in time
Probe performance was good in single-task condition and did not depend on location of T1 relative to T2
Dual-task performance – probe performance was much poorer

25. Attentional blink Procedure
Target (T1), say T is white and the Probe is presented at variable serial positions after the target

26. Attentional blink
Note: single task performance does not vary by serial position
dual-task performance, having to report the target (T1), reduces performance when when T2 probe was presented within 100 – 500 ms of T1

27. Attention Conclusions
It suggests that processing an earlier stimulus (T1) prevents processing of a subsequent stimulus for a brief period of time
Called an attentional blink

28. Attention Repetition blindness
Failure to detect the subsequent appearance of a stimulus when stimuli are presented rapidly
E.g., Kinwischer (1997) showed a sequence of pictures of objects rapidly; results showed that when two pictures were identical, participants were less likely to report second instance of the object even though another picture was presented in between

29. Attention Repetition blindness
Similar findings were observed when the same object depicted from a different angle, same object was presented, but of a different size

30. Neuropsychology of attention
Exogenous and endogenous attention
Background
when we wish to examine a stimulus in more detail our eyes move and focus on that object (visually orient to a stimulus)
this permits the image of the stimulus to fall on that part of the retina with the greatest acuity
we know now that it is possible to orient to a stimulus without actually moving one’s eyes

31. Neuropsychology of attention
Exogenous and endogenous attention
Background
recordings of neurons from monkey brains show that their rate of firing is increased when monkeys attend either overtly or covertly to a target location
brain regions were: the superior colliculus, a part of the thalamus called the pulvinar, and a part of the cortex called the posterior parietal lobe

32. Neuropsychology of attention
Exogenous and endogenous attention
Visual orienting cueing task
cue on a VCR indicates the probable location of the subsequent target
central cue is an arrow in the centre of VCR indicating the probable target location (endogenous, voluntary, controlled)
Arrow cue is endogenous because it is a symbol that must be interpreted; covert attention
peripheral cue is brightening of a box at one of the two target locations (exogenous, automatic)

33. Neuropsychology of attention
Exogenous and endogenous attention
comparisons
target is presented without giving a cue in advance
target is presented after giving an incorrect cue (occasionally)
control
eye position monitored to insure that it remains fixed

34. Neuropsychology of attention
Exogenous and endogenous attention
subjects responded more quickly when the cue correctly orients subjects compared to no cue condition
subjects responded more slowly when the cue misorients subjects compared to the no cue condition

35. Neuropsychology of attention
Exogenous and endogenous attention
Similar findings were observed when peripheral (endogenous) cues were used

36. Neuropsychology of attention
Exogenous and endogenous attention
Visual orienting cueing task comparison group and control
results support the notion that attention shifts can occur covertly without any change in eye position
subjects need only about 500 ms warning in order for it to facilitate target detection latency
attention shifts can be controlled either centrally in visual field (via controlled processing) or peripherally (via automatic processing)

37. Neuropsychology of attention
Exogenous and endogenous attention
role of the parietal lobe
lesions in the parietal lobe, particularly on the right side, can cause patients to overlook sensory information on the side opposite to the lesion
phenomenon is called “visual neglect”; neglect can also be observed in other sensory modalities

38. Neuropsych results from visual neglect

39. Neuropsych results from visual neglect

40. Neuropsych results from visual neglect

41. Neuropsychology of attention
Exogenous and endogenous attention
visual orienting experiment with parietal patients
without a cue patients generally respond faster when the cue is on the ipsilateral to the lesion side and slower when it on the contralateral side
Recall: ipsilateral: same side as lesion, and therefore processed by undamaged hemisphere; contralateral is other side to lesion

42. Neuropsychology of attention
Exogenous and endogenous attention
visual orienting experiments with parietal patients
when parietal patients are cued to side, there is little difference between detecting stimuli to either side; therefore ability of many (although not all) patients appears to be intact
when patients are miscued, patients are slowed, particularly when the target is on the contralateral side
(recall contralateral processed by lesioned side)

43. Left hemisphere damage

44. Right hemisphere damage

45. Neuropsychology of attention
Based on a series of studies Posner and his colleagues have argued that the major deficit in parietal patients is that they have difficulty disengaging
clinically parietal patients tend to neglect the contralesional side of objects irrespective of where in the visual field the objects are located
in a further experiment Posner showed that subjects had difficulty shift

46. Neuropsychology of attention
in a further experiment Posner showed that subjects had difficulty shifting in the contralesional direction regardless of the visual field in which the stimuli were presented

47. Attention Object-based attention
When attention is directed toward an object, all parts of that object are selected for further processing (Duncan, 1984)
Duncan (1984) investigated whether 2 features associated with the same object were processed better than 2 features associated with two different objects

48. Attention Object-based attention
Stimuli were a rectangular box (big, small) with a gap (left, right) and a line (upright, slanted) either drawn dotted or dashed through the box

49. Object-based attention

50. Attention Object-based attention
Stimuli were a rectangular box (big, small) with a gap (left, right) and a line (upright, slanted) either drawn dotted or dashed through the box
Participants were more accurate when they made 2 judgments about the same object (e.g., the box) than 2 judgments about two different objects (box, line)
Conclusion. Attention can be directed to a single object; i.e., object-based attention

51. Attention Object-based attention
Stimuli were a rectangular box (big, small) with a gap (left, right) and a line (upright, slanted) either drawn dotted or dashed through the box
Participants were more accurate when they made 2 judgments about the same object (e.g., the box) than 2 judgments about two different objects (box, line)
Conclusion. Attention can be directed to a single object; i.e., object-based attention

52. Attention Object-based attention -- neuroimaging
Neuroimaging (fMRI) was used to investigate object-based attention (Downing, Liu, Kanswischer, 2001)
Participants were shown superimposed semitransparent pictures of a house and face
On each trial either the house or face oscillated slightly along one axis while the other object remained stationary

53. Attention Object-based attention -- neuroimaging
Neuroimaging (fMRI) was used to investigate object-based attention (Downing, Liu, Kanswischer, 2001)
Participants were shown superimposed semitransparent pictures of a house and face
On each trial either the house or face oscillated slightly along one axis while the other object remained stationary

54. Attention Object-based attention -- neuroimaging
Houses and faces were used because previous research has shown that different brain regions respond to faces, fusiform face area (FFA), and to objects (like houses and places), parahippocampal place area (PPA)

55. Attention Object-based attention -- neuroimaging
Participants were instructed to attend either to the motion (attend moving) or to the position of the stationary object (attend static)
Note: location-based selection would not allow for efficient selection of one object since both objects are in the same location

56. Object-based attention

57. Attention Object-based attention -- neuroimaging
Static condition: higher activation to the face (when house moving) in FFA and to the house in PPA (when face moving)
Attend condition: higher activation to face moving in FFA and to the house moving in PPA
Conclusion: provide support for object-based attention, suggest that more than one feature is selected simultaneously, and that selection by location is not the only basis for selection

58. Attention Attention– neuroimaging exogenous and endogenous attention
Corbetta and Shulman (2002) investigated brain regions associated with exogenous and endogenous attention

59. Attention Attention– neuroimaging exogenous and endogenous attention
Results showed that when attention was directed to a location prior to presentation of a target (endogenous attention), a network of frontal and parietal regions was activated including the intraparietal sulcus (IPS), the superior parietal lobule (SPL), and the frontal eye fields (FEF)

60. Attention Attention– neuroimaging exogenous and endogenous attention
When attention was unexpectedly directed (exogenous attention), a more ventral network, which included the temporal-parietal junction (TPJ) and ventral frontal cortex was activated

61. Attention Attention– neuroimaging exogenous and endogenous attention
This network may be involved in the identification of unexpected stimulus which interrupts processing of the voluntary attentional system

62. Attention Broadbent’s filter model (1958)
landmark model because it used an information processing analysis to develop a model to account for performance on selective listening tasks

63. Attention Broadbent’s filter model
task modelled: subject presented different messages played simultaneously to different ears
task is very difficult, but why
Broadbent’s model proposed that simultaneous processing is difficult to because pattern recognition has limited capacity; only if information is processed by the pattern recognition system can it interpreted and remembered

64. Attention Broadbent’s filter model
sample experimental paradigm: simultaneous presentation to the two ears of pairs of digits with a .5 second delay between successive pairs of digits
left ear right ear
7 3
4 1
1 5

65. Attention Broadbent’s filter model
condition 1: report digits in any order
subjects almost always reported digits by one ear and then the other
condition 2: report digits by order of presentation

66. Broadbent 1954

67. Broadbent’s model Sensory Store Pattern Filter Short-term Recognition
Memory store

68. Attention Processing assumptions of Broadbent’s model
sensory stores have relatively large storage capacity, but information decays over time
perceptual channel (filter) has much smaller capacity and can accept 1 digit at a time
it takes time to switch attention from one ear to the other

69. Attention
Note: Broadbent’s model is an early-selection model because selection (filter) occurs prior to the analysis of the meaning
thus, selection must be made on the basis of the physical characteristics of the incoming information
thought experiment: How many people have heard their name mentioned in a conversation that they were not following?

70. Attention Dichotic listening and shadowing
problems with thought experiment
uncontrolled
person who hears voice in unattended conversation may be switching attention
to address these problems Cherry (1953) developed the dichotic listening and shadowing paradigm

71. Attention Dichotic listening and shadowing results
Treisman (1960) compound sentence study
Jordan dunked the ball, and his basket won the game
Marsha Ball sings marvelously, but her piano playing is incredible
results showed that participants tended to switch ears when meaning was switched

72. Attention Filter attenuator model
Treisman proposed that the filter acts more like an attenuator; ie, it allows for some information to come through

73. Attention
Late selection model (Deutsch and Deutsch (1963) and Norman (1968)
according to these models information is processed to the level of meaning, but the limitation is in determining which information is to be selected into memory

74. Late Selection Model Filter Sensory Filter Store Short-term Pattern
Memory store
Pattern
Recognition
Filter

75. Testing early vs late selection models of attention
Initial tests
Treisman and Geffen (1967)
used a dichotic listening and shadowing task to evaluate early vs late selection models of attention
participants were instructed to tap table whenever they heard a target word in either the shadowed or unshadowed message
results: detected target word 87% of time in shadowed message, but only 8% of time in unshadowed message

76. Testing early vs late selection models of attention
Treisman and Geffen (1967) cont’d
These findings are consistent with attenuation hypothesis
counterargument: shadowing and tapping constitute two responses and consequently there is interference
Here the idea is that planning 2 different responses at the same time results in interference

77. Capacity models of attention
Kahneman (1973) proposed that people have a limited capacity to process information
thus, the function of attention is to allocate processing resources to various inputs
one way to circumvent this limitation is to practice tasks so that they can be performed more automatically

78. Capacity models of attention
four factors that control attention
enduring dispositions
e.g., sudden motion, mention of name
momentary intentions
reflect current goals; e.g., experimental instructions
evaluation of demands
e.g., if two tasks exceed capacity, prioritize
arousal

79. Theory of biased or integrated attention
Developed by Desimone & Duncan (1995); Duncan (1997)
More recent theory
Note: in contrast to earlier theories of attention it is concerned not only with behavioral data but also with findings from neural studies

80. Theory of biased or integrated attention
Theory holds that attention is a form of competition between different inputs, which can take place at all stages of processing and between different brain regions
Input receiving most resources is most completely processed

81. Theory of biased or integrated attention
E.g., suppose you are at a party and hear glass break; although unexpected, this stimulus is salient and would compete with general party noise
Competition takes place at auditory cortex and salience of stimulus results in it being thoroughly processed

82. Theory of biased or integrated attention
Theory holds that attention is not location based (a spotlight) or does not occur because of a particular bottleneck
Instead attention is part of perceptual processing, which is necessary because not all aspects of the environment can be processed
Attention biases or influences the degree to which different aspects of the environment are processed

83. Theory of biased or integrated attention
Source of the bias can be endogenous (e.g., goals, knowledge) or exogenous
Competition can occur in multiple brain regions including those posterior brain regions that process early aspects of stimuli (e.g., color) and more anterior brain regions that are influenced by endogenous factors

84. Theory of biased or integrated attention
Note: if more posterior brain regions are biased in their processing this will affect more anterior brain regions

85. Theory of biased or integrated attention
Endogenous and exogenous attention studies (see Posner, Corbetta studies) can be interpreted in this way
For example, in the valid cue condition, there will between cooperation between the endogenous cue and location of the target
In the invalid cue condition there is competition between the endogenous cue and location of the target

86. Theory of biased or integrated attention
Summary
The theory of biased competition emphasizes notion that bias or strength is a product of top-down and bottom-up influences
It occurs in a distributed network of brain regions in which there are competitive and cooperative interactions among brain regions