1. PSY 323: Cognition
Chapter 4: Attention

2. Different Aspects of Attention
The ability to focus on specific stimuli or locations
Selective Attention
Trying to attend to one task while ignoring the another
Auditory
Visual
Distraction
One stimulus interfering with the processing of another stimulus

3. Different Aspects of Attention
Divided Attention
Trying to attend to two stimuli at once and making multiple responses rather than making one response to multiple stimuli
Automatic Processing
Attentional Capture
A rapid shifting of attention usually caused by a stimulus
Visual Scanning
Movements of the eyes from one location or object to another

4. Attention as Information Processing
Broadbent’s Filter Model of Attention
Sensory
Memory
(Input)
Filter
Detector
STM
(Output)
Attended Message
Broadbent (1958)
Proposed that information passes through these stages
Often referred to as the bottleneck model

5. Selective Attention: Auditory
Procedure
Dichotic Listening Experiment
Shadowing task
Any task where two streams of auditory information are presented simultaneously, one to each ear (generally over headphones).
Subjects are required to attend to one ear only.
Cherry (1953)

6. In Shadowing Task… Results
Listeners seldom noticed the unattended message being in a foreign language or in reversed speech
However, they nearly always noticed physical changes in the unattended message
Interpretation
People can shadow accurately  
Unattended auditory information receives very little processing
Cherry (1953)

7. Attention as Information Processing
Attention as Information Processing
The “Cocktail Party Effect”
The phenomenon that occurs when someone is selectively listening to one message among many
Researchers included word in unattended message on 35 consecutive trials
Participants were unaware of this
Moray (1959)

8. Filter Theories: Early Selection
Broadbent (1958)
Attentional filter operates after sensory processing but prior to meaningful semantic processing
Explains why ignored messages in shadowing task can’t be remembered—they were not semantically processed
Explains why sensory features of the ignored message (e.g., pitch) are processed and remembered

9. Modifying Broadbent’s Model
Modifying Broadbent’s Model
Moray (1959)
Procedure
Shadow the message in one ear and ignore the message in the other ear
Presented listener’s name in unattended ear
Results
Over 30% of participants detected their name
Interpretation
Broadbent was wrong

10. Limitations to Broadbent’s Model
Limitations to Broadbent’s Model
Broadbent’s Model Could Not Explain
Participant’s name gets through
Participants can shadow meaningful messages that switches from one ear to another
Effects of practice on detecting information in unattended ear (e.g., detect digit in unattended ear for naïve and practiced participants)

11. Other Evidence Against Broadbent
Gray & Wedderburn (1960)
Procedure
Participants were asked to shadow the message presented in one ear
Results
Participants typically responded “Dear Aunt Jane”
Interpretation
Participants’ attention appeared to be jumping from one ear to another
The “Dear Aunt Jane” experiment 

12. Attenuation Theory of Attention
Treisman (1964)
Proposed that selection occurs in two stages
Stage 1
Replaced Broadbent’s filter with an attenuator
This analyzes incoming message in terms of its physical characteristics, its language, and its meaning
Language and meaning can be used to separate the messages
The analysis of the message proceeds only as far as is necessary to identify the attended message

13. Attenuation Theory of Attention
Treisman (1964)
Stage 1
“Leaky filter” – both attended and unattended messages get through the attenuator but only attended message is at full strength
Unattended messages are attenuated (still present but weaker than attended message)
Stage 2
The final output is determined when the message is analyzed by a dictionary unit which contains stored words, each of which has a threshold for being activated
Low threshold words can be detected because it is common or especially important
See next slide 

14. Attenuation Theory of Attention
Treisman (1964)

15. Attenuation: The Dictionary Unit
Treisman (1964)
Attenuation: The Dictionary Unit
The message gets passed on to the dictionary unit
Threshold = Smallest signal strength that can just be detected
Easily detected

16. Attenuation explains…
Treisman (1964)
Hearing your own name when that stream is supposed to be ignored
Switching channels in order to make a complete sentence

17. Late Selection Model of Attention
Effects of an Unattended Word
MacKay (1973)
Attended Ear:
“The boy threw a rock at a bank”
Unattended Ear:
“Scissor...ladder…money…finger
Question:
Where did the boy throw the rock?
Answer:
At a financial bank

18. Late Selection Model of Attention
MacKay (1973)
Attended Ear: “The boy threw a rock at a bank”
Unattended Ear: “ Scissor...ladder…river…finger
Question: Where did the boy throw the rock?
Answer: At the riverbank

19. Late Selection Model of Attention
Interpretation
The biasing word was affecting the participant’s choice
The word must have been processed at the level of meaning even though it was unattended
MacKay (1973)

20. Late Selection Model All stimuli is processed to the level of
Deutsch & Deutsch (1963)
Late Selection Model
Working
Memory
Sensory
Stores
Long
Term
Memory
All stimuli is processed to the level of
meaning, relevance determines further
processing and action

21. So, which type of model is right?
Early-Late Controversy
Early selection can be demonstrated under some conditions
Late selection can be demonstrated under other conditions

22. Processing Capacity & Perceptual Load
The idea that a person has a certain cognitive capacity which can be used to carry out various tasks
Perceptual Load
The amount of a person’s cognitive resources needed to carry out a particular cognitive task
Low-load task
Easier; cognitive resources are left over
Can process additional information
High-load task
Difficult; requiring most of someone’s cognitive resources
Only selected items are processed

23. Load Theory of Attention
Lavie (2005)
Posits that the amount of cognitive resources that remain as a person is carrying out a primary task determines how well the person can avoid attending to task-irrelevant stimuli

24. Selective Attention: Visual
The Stroop Test (1935)
Names of words cause a competing response
Task–irrelevant stimuli are extremely powerful

25. Selective Attention: Visual
The Stroop Test (1935)

26. Selective Attention: Visual
The Stroop Test (1935)

27. Overt & Covert Attention
Shifting from one place to another by moving your eyes
Covert Attention
Eyes are stationary
What we are attending to can be seen from our eye movements:
Saccadic eye movement: rapid shifts of the eyes
Fixations: short pauses on points of interest

28. Find Bob Dylan’s face in this group.

29. Eye Tracking
Tracking where the eyes are looking

30. Visualizing Eye Tracking Data
Example: How do people look at a complex schematic?

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

32. Overt Attention Stimulus Salience
Areas that stand out from the background
Scene Schema
This is what we think the scene should contain

33. Covert Attention
Directing your visual attention without moving your eyes
Precueing Procedure
The participant is presented with a cue that indicates where a stimulus is most likely to appear
Location-based attention – how attention is directed to a specific location or place

34. Attention to Location Posner et al. (1978)
Procedure for (a) valid trials and (b) invalid trials in Posner et al.’s (1978) precueing experiment; (c) the results of the experiment. The average reaction time was 245 ms for valid trials but 305 ms for invalid trials.
Posner et al. (1978)

35. Posner Cuing Paradigm Results
Valid trials made up 80% of trials; invalid made up 20% of trials RT
Invalid Cue
Valid Cue
Posner et al. (1978)

36. Covert Attention Interpretation
Information processing is more effective at the place where attention is directed
Attention is like a spotlight that improves processing when directed toward a particular location
Posner et al. (1978)

37. Covert Attention Attention to Objects
When we see the world, we often process it into objects
Object-based attention
When attention is focused to one part of an object, it spreads throughout the whole object

38. Attention to Objects Two objects, side by side
Distance from one end of object to other end = distance from one object to another on the same end
Cue one end of one object; pause
Egly, Driver, & Rafal (1994)

39. Attention to Objects Procedure Present target
Valid target (same location as cue)
Invalid/same object (same object, different end)
Invalid/different object (different object, same end)
Wholly invalid
(different object,
different end)
Egly, Driver, & Rafal (1994)

40. Results Egly, Driver, & Rafal (1994)
RT: A (Valid) < B (Invalid/SO) < C (Invalid/DO)

41. Results
Subjects are fastest when the target is at the same location as the cue
When the target is invalid, subjects are faster in Invalid/SO than Invalid/DO

42. Results
The distance attention has to move in Invalid/SO and Invalid/DO is the same
Distance cannot be the cause of the results
Attention must spread
to the entire object
when part of it is cued
Egly, Driver, & Rafal (1994)

43. Comparison Which one is right?
They both are, depending on the task and conditions
Attention can be based on where a person is looking in the environment (location-based attention) and where a person is looking on a specific object (object-based attention)

44. Divided Attention “the Mets will win it all this year...”
“Better drop this class,
Dr. Weiss is the
toughest prof at
UIU…”
“Dr. Weiss, uh what
about the Mets?”

45. The Effect of Practice Spelke, et. al (1976)
Task: Read short stories and take dictation (write words spoken to them)
At first, performance was awful
After 85 hours of practice, performance was much better

46. Divided Attention Can Be Achieved With Practice: Automatic Processing
Schneider & Shiffrin (1977)
Procedure
Give subjects a “memory set” - up to 4 letters or numbers

47. Divided Attention Can Be Achieved With Practice: Automatic Processing
Procedure
Was an object from the memory set present anywhere in the stream?
When one number/letter was in the memory set, it was never a distractor on the next trial
A distractor on the current trial was never in the memory set on the next trial

48. Schneider & Shiffrin: Results
Beginning: 55% accurate
900 trials: 90% accurate
600 trials: Participants reported automatic processing (no need to try hard to do the task)
Occurs without intention
Uses few cognitive resources

49. Automatic processing outside the lab…
Occurs for well-practiced tasks
When people starting thinking about things, they make errors or at least not as efficient

50. Divided Attention & Driving
Strayer & Johnson (2001)
80% of crashes & 67% of near crashes people were distracted
Cell phones increase the risk of crashes to level similar to BAC of .08

51. What happens when we don’t attend?
Mack & Rock (2000)
Inattentional Blindness
Research on this phenomenon known suggests that unless we pay close attention, we can miss even the most conspicuous events

52. Sights unseen? Inattentional Blindness
Participants were asked to focus on a cross
They often failed to notice an unexpected object, even when it had appeared in the center of their field of vision 
Mack & Rock (2000)

53. Inattentional Blindness
Neisser et al. (1979)
In this one minute video, there will be two basketball teams
You task is to count the passes of just one team

54. Inattentional Blindness
Simons & Chabris (1999)

55. Change Blindness
People fail to detect substantial features of photographs and real world experiences
They seem to lack a precise visual representation of their world from one view to the next
Daniel Simons
Levin & Simons study (1997) 
Levin & Simons study (1998) 

56. Choice Blindness Johansson, Hall, Sikstrom, & Olsson (2005)
Participants failure to detect a mismatch from their original choice to what was later presented to them as their original choice (but was not)
Petter Johansson 

57. Attention & Experiencing a Coherent World
Binding
Visual attention is needed for integrating stimulus features (e.g., color, shape, and location) in perception
Allows us to form a coherent object

58. Attention & Experiencing a Coherent World
Feature Integration Theory
Preattentive Stage
Objects are analyzed separately by our brain
We do this automatically
Focused Attention Stage
Free-floating features are combined
Leads to perception
Gestalt idea
Treisman & Schmidt (1982)

59. Credits
Some of the slides in this presentation prepared with the assistance of the following web sites: