How to be successful in this course

1
How to be successful in this course

• Pay lots of attention in the very beginning (like
  now would be good)
• Review your research methods
• Come talk to me personally about how youre doing
• As soon as the final project begins to loom, go
  to the writing center keep going back

2
Demonstration

• What was this experiment about?
• What aspect of cognition?
• What is the hypothesis?
• What are the IV and DV?
• How would you go about analyzing the data to
  answer the question?

3
Readings assigned

• Iconic Memory and Masking (19-24)
• Section on Donders and Sternberg (25-30)
• Methodological Issues in Reaction Time (31-33)
• Priming both parts (35-50)
• For next week
• Half century of research on the Stroop Effect
  (51-53)

4
Excel Assignments

• Located in the reading packet.

5
Interests of Cognitive Psychology

• Sensation and Perception
• Learning
• Memory
• Language
• Reasoning and Problem Solving
• Decision Making

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The Research Cycle
7
The Research Cycle
Draw Conclusions
Replication Project
Data Collection Analysis
Communicate
8
The Research Cycle
Question
Draw Conclusions
Design
Final Project
Data Collection Analysis
Communicate
9
Science

• What is science?
• Science is a means by which we can gain evidence
  that either supports or fails to support a
  particular claim.
• What is the purpose of science?
• The purpose of science is to establish general
  laws that will allow us to make predictions
  about future events -Braithwaite, 1953

10
Scientific Method

• Empirical -- it involves the direct measurement
  of observable events.
• Circular

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OBSERVATION

• First, one observes an event, either in a
  laboratory or in the real world.

12
THEORY

• a set of formal statements that explains how and
  why certain events are related to one another
• Theories are not directly observable they are
  supported or refuted with research.

13
HYPOTHESIS

• tentative explanation or prediction about some
  phenomenon
• a testable proposition that is logically derived
  from the theory

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Two Forms of Hypotheses

• Theoretical Hypothesis the bigger question in
  which you are really interested. The hypothesis
  stated in conceptual or abstract terms (relating
  to a general principle.
• Operational Hypothesis testable, concrete terms
  used for a particular experiment. Hypothesis
  stated in concrete terms (what is actually
  measured and manipulated

15
Operational Definition

• defines a variable in terms of the specific
  procedures used to measure it,
• and in so doing...
• translates the abstract into something observable
  and measurable.
• For example
• intelligence as IQ score
• memory as number of words recalled

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TEST

• Conduct empirical research!
• Report findings to the community.

17
Evidence vs. Proof

• We measure experimental results using statistical
  analyses that tell us whether an effect is likely
  to have occurred by chance.
• Even if the difference is found to be
  significant, the hypothesis has not been
  proven-- only supported.

18
Masking Word FrequencyLexical Priming
19
Iconic Memory and Masking

• What is iconic memory?
• 1. Information in the form of visual input
  reaches your retina and visual field.
• 2. This excites your rods and cones which relays
  the information to your visual cortex.
• 3. The information is briefly stored in a medium
  that experiences rapid decay.

20
Sperlings Question

• How many things can we process
• comprehend
• remember
• in a single glance?

21
The Sperling Paradigm (1960)
22
A bunch of letter will be flashed on the screen.
Try to remember as many letters as you can.
23

24
L T R F
25

26
S L W FJ M B ZX P D Q
27

28
Sperlings method

Fixation Point
Varied number of letters
Presented very briefly(50 ms)
Report What letters did you see?
29
Findings

• When the array had 4 or fewer letters subjects
  reports were near perfect.
• As the number of letters presented increased the
  number subjects could report averaged about 4.3
  items regardless of the array size.

30
With a 3x4 array, subjects could report about a
third (4 out of 12) of the letters.
31
What do these findings suggest about how much we
comprehend in a single glance?(how much, how
long?)
32
Capacity versus Duration

• To further examine the effects of capacity (size)
  versus the duration (decay) of iconic memory,
  Sperling modified his method to compare a partial
  report condition to his original, whole report
  condition.

33
Same as the first, except this time after
flashing the letter array, I will shout out
either top, middle or bottom and you must
try and recall only the letters from that row.
34

35
R N Z LO F G T E S B W
36

37

Fixation Point
Partial Report
Presented very briefly (50 ms)
High Medium Low
Tone
Report based on tone
38
Partial Report
High
Subjects could report an average of 3.04 letters
from a row with 4 letters.
39
Partial report
Whole report
High
Report from entire array 4.3/12 or 36
Report from one row 3.04/4 or 76.
40
Interpretation of Sperlings findings

• Much of the information from the matrix is
  available after the array has disappeared from
  sight.
• This information decays quickly and the remainder
  is gone by the time three or four of the letters
  can be reported.

41
In the whole report condition
What the subject sees
Iconic memory
42
In the whole report condition
What the subject sees
Iconic memory
For 50 ms
43
In the whole report condition
What the subject sees
Iconic memory
50 ms
Recall
44
In the whole report condition
What the subject sees
Iconic memory
50 ms
Recall
45
In the whole report condition
What the subject sees
Iconic memory
50 ms
Recall
46
In the whole report condition
What the subject sees
Iconic memory
50 ms
Recall
47
In the partial report condition
What the subject sees
Iconic memory
48
In the partial report condition
What the subject sees
Iconic memory
For 50 ms
49
In the partial report condition
What the subject sees
Iconic memory
What the subject heard
High
50 ms
Recall
50
In the partial report condition
What the subject sees
Iconic memory
50 ms
Recall
51
In the partial report condition
What the subject sees
Iconic memory
50 ms
Recall
52
In the partial report condition
What the subject sees
Iconic memory
50 ms
Recall
53
Other iconic memory findings

• Duration (delayed tone) The partial report
  advantage decreases rapidly over the first 250
  ms. By 300 ms, there is no advantage of partial
  over whole report.
• Level of Processing (type of cue to direct
  partial report)
• Numbers vs letters--no partial report advantage
• Color, size, and shape--partial report advantage

54

55
S L W FJ M B ZX P D Q
56
Averbach Coriell

• Attempted a conceptual replication of Sperlings
  finding
• Used visual cues rather than auditory cue (i.e.
  tone).

57
Averbach Coriell
Bar marker
Circle marker
Marker appeared after the stimulus was turned
off.
58
Averbach Coriells findings

• With bar marker, the estimated duration of
  iconic memory was 250-300 ms. replicating
  Sperlings estimation.
• With circle marker, performance was very low
  compared to performance in the bar marker
  condition.

59
Backward masking

• Performance is degraded when a mask appears at
  the same spatial location as the stimulus.
• Iconic image is susceptible to interference from
  subsequent stimuli.

60
Iconic Memory

• Large capacity
• Short duration
• Stored on the level of physical feature analysis
  (levels of processing exist!)
• Vulnerable to interference

61
Backward masking

• Performance is degraded when a mask appears at
  the same spatial location as the the stimulus.
• Iconic image is susceptible to interference from
  subsequent stimuli.

62

• What did Sperling manipulate?
• What did Sperling observe?
• What kinds of controls might Sperling have used?
• Does partial report superiority prove iconic
  memory exists?
• What other ways could iconic memory theory be
  tested?
• What other things would be interesting to know
  about iconic memory?

63

• What was Averbach and Coriells research
  question?
• What other questions might we ask about masking?

64
Donders Reaction Time
65
Franciscus Donders

• Physiologist during the 19th Century
• Studied ophthamology
• Pioneered work on mental chronometry
• Inferring differences in cognitive processing
  from differences in Reaction Time

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Reaction Time in a Simple Task
Press the space bar
67
Reaction Time in a Harder Task
Press the space bar
Dont Do Anything
Measuring the time that elapses between light and
key press
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Reaction Time in an Even Harder Task
Press the space bar
Press the Enter key
Measuring the time that elapses between light and
key press
69
So whats the difference?
Stimulus Detection Motor Response Execution
Stimulus Detection Mental Recognition Motor
Response Execution
Stimulus Detection Mental Recognition Motor
Response Selection Motor Response Execution
70
Speed versus Accuracy in RT Studies
vs.
71

• Why is accuracy important if your dependent
  variable is reaction time?
• You want the fastest possible reaction times in
  order to show an irreducible minimum time for the
  process you are measuring.

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However...

• You need to demonstrate that your fast reaction
  times are not the result of guessing or
  anticipation

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For example...

• Condition RT (ms) Error
• 1 560 2
• 2 790 10
• 3 425 20
• 4 1250 1

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Semantic Memoryand Priming
75
Bottom-Up versus Top-Down
76
TOP
Concept-drive Whole-to-part Idea level Knowledge
Data-driven Part-to-whole Stimulus
level Sensations
BOTTOM
77
Example Can you read this?
78
Which was it?
79
Which was it?
80
The distinction

• Is useful
• Processes work together
• No task is involves just one
• Use procedures to isolate affect of each

81
What is Semantic Memory?

• memory for words, concepts, rules, and abstract
  ideas
• used when we read, talk, or do mental problem
  solving.

82
Feature Comparison Model

• memory is organized by lists of features or
  attributes

83

• birds
• have wings
• eat worms
• fly
• True or False?
• A robin is a bird.
• A tiger is a bird.
• A penguin is a bird.

84
2 Stage Process

• Stage 1 compares all features of two items
• Stage 2 needed if stage 1 results in
  intermediate similarity

85
Spreading Activation

• When a concept is mentioned, the node
  representing that concept is activated.
• This activation then spreads to connected
  concepts (nodes).
• The further it spreads the weaker the activation
  becomes.

86
Semantic Networks
CAT
COLLAR
DOG
PET
LEASH
TAIL
SPOT
BULL
ANIMAL
87
If the word BULL is presented,

• Is this a word?
• BULL

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then the concept BULL is activated.
CAT
COLLAR
DOG
LEASH
TAIL
SPOT
BULL
ANIMAL
89
And, the activation spreads to connected concepts.
CAT
COLLAR
DOG
LEASH
TAIL
SPOT
BULL
ANIMAL
90
So, those concepts become activated (but the
activation weakens as it spreads).
CAT
COLLAR
DOG
LEASH
TAIL
SPOT
BULL
ANIMAL
91
Because DOG is already activated, the subject
will be able to respond to DOG faster than they
can respond to COLLAR.
92
CAT
COLLAR
DOG
LEASH
TAIL
SPOT
BULL
ANIMAL
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Priming

• Priming occurs when a previously related concept
  is shown prior to the target concept, thus,
  activating the target concept and making it more
  accessible.

94
Priming An example of Top-down

• Lexical decision task
• Subject is presented with a letter-string
• WORK or RKOW
• Task is to say whether or not the string is a
  word.
• Manipulation
• The word the precedes the target word is either
  related or unrelated.

95
A couple of examples where one can find Priming
effects...

• Lexical Decision Tasks
• Person Perception

96
Priming in Person Perception Tasks

• Activate a schema or stereotype
• Provide an ambiguous stimulus with respect to the
  trait of interest that also indicates whether the
  person is of the stereotyped group or not
• Have subjects rate the individual on the target
  trait (and others)
• If priming occurs, ratings on target trait will
  vary with stereotype, but not on the other traits