Introduction to Cognitive Psychology

1
Introduction to Cognitive Psychology
2
What is Cognitive Psychology?

• Cognitive psychology is the study of mental
  processes

3
What is Cognitive Psychology?

• Cognitive Psychology versusBehaviorism
• Behavioral Psych how S maps onto R
• Cognitive Psych what happens in the mind
• Both can use formulas to map S onto R
• The difference is level of complexity

S
Environment
Mind
R
4
What is Cognitive Psychology?

• Cognitive Psychology versusNeurobiology
• Neurobiology how does the brain do it?
• Cognitive Psych how does the mind do it?
• Both can use neurons to describe mind
• The difference is behavior (the big picture)

5
What is Cognitive Psychology?

• Metaphor mind Windows
• Behaviorists
• What happens when I press Alt-Tab? Cool! It
  switched to my last open application!! But how
  does that work?
• Neurobiologists
• Check this out, the harddrive and the RAM are
  both connected to the motherboard! But what does
  that mean?
• Cognitive Psychologists
• Pressing Alt-Tab switches me between
  applications, and I know that Windows uses STM
  Lets propose a model of Windows where it stores
  which apps are open in STM, and when a user hits
  Alt-Tab, it switches between open apps.

6
What is Cognitive Psychology?

• Cognitive Psychology versusArtificial
  Intelligence (AI)
• AI whats the best way to do this?
• Cognitive Psych how do humans do this?
• Both try to model some form of mind
• The difference is fidelity
• Brain is optimal If AI truly wants to find
  optimality they should study Cognitive Psychology.

7
Why study Cognitive Psychology

• Understanding the mind
• Education
• Medicine
• Therapy
• Artificial Intelligence
• Tool/Interface Design
• Gaming/Entertainment
• Etc.

8
What is involved in Cognition

• The book lists
• Perception, Attention, Memory, Problem-Solving,
  Language, Reasoning, Decision-making
• This is not a comprehensive list of mental
  processes
• These processes are not independent of one
  another
• E.g. attention may be part of perception
  language may be part of memory and
  decision-making, etc.

9
Complexity of Cognition
10
Figure 1.1 (p. 3) - Complexity of
CognitionSarah is walking toward her friend, who
is waving in the distance. She is aware of her
friend, but has little awareness of the stranger
who is passing on her right, even though he is
much closer.
11
What we are aware of
The complexities of cognition are usually hidden
from our consciousness.
12
The Magic of Cognition

• In our lives we are likely to NEVER encounter the
  same retinal input twice!
• EVER!
• We will learn about categorization and invariant
  representation

13
The Magic of Cognition

• The Stroop effect
• We have automatic reading routines
• It is hard to stop well-practiced routines from
  executing
• This is the difference between experts and novices

14
Figure 1.5 (p 8) - Hemholtzs unconcious
inferenceThe display in (a) looks like (b) a
gray rectangle in front of a light triangle but
it could be (c) a gray rectangle and a six-sided
figure that are lined up appropriately.
Complexity of Perception Expectations
15
The Herring illusionThe diagonal lines give the
impression of moving forward- the lines look
like optic streaks (streaks of neural activation
in the retina)When moving forward, straight
lines (like doorways) start looking like curves
on the retina.
Complexity of Perception Expectations
16
The Magic of Cognition

• These types of phenomena give us a hint as to how
  cognition works
• E.g. Do you process all of the information that
  falls on your retina?
• It may be that we have a perfect representation
  of the world
• It may be that we make gross estimations based on
  prior experience
• DEMO

17
Complexity of Cognition
The understand-the-brain jigsaw puzzle is
particularly daunting To get a sense of the
difficulty, imagine a jigsaw puzzle with several
thousand pieces. Many of the pieces can be
interpreted multiple ways, as if each had an
image on both sides but only one of them is the
right one. All the pieces are poorly shaped so
you cant be certain if two pieces fit together
or not. Many of them will not be used in the
ultimate solution, but you dont know which ones
or how many. Every month new pieces arrive in the
mail. Some of these new pieces replace older
ones, as if the puzzlemaker was saying, I know
youve been working with these old puzzle pieces
for a few years, but they turned out to be wrong.
Sorry. Use these new ones instead until future
notice. Unfortunately, you have no idea what the
end result will look like worse, you may have
some ideas, but they are wrong. - Jeff
Hawkins, On Intelligence
18
Methodology
19
How CogPsych is studied

• Donders reaction time experiment

20
Figure 1.3 (p. 6)A modern version of Donders
(1868) reaction time experiment. (a) the simple
reaction-time task and (b) the choice
reaction-time task. For the simple time reaction
text, the participant pushes the J key when the
light goes on. For the choice reaction time test
the participant pushes the J key if the left
light goes on, and the K key if the right light
goes on. The purpose of the Donders experiment
was to determine the time it took to decide which
key to press for the choice reaction time test.
21
Figure 1.4 (p. 7)Sequence of events between
presentation of the stimulus and the behavioral
response, in Donders experiment. The dashed
line indicates that Donders measured reaction
time, the time between presentation of the light
and the participants response. (a) simple
reaction-time task (b) choice reaction-time task.
22
How CogPsych is studied

• Behavioral and physiological

23
Figure 1.9 (p. 15)Updated sequence of events
between stimulus and response, taking into
account the physio-logical response. A, B, C
show relationships that can be measured. The
mental response must be inferred from these
relationships.
Correction
Stimulus
Physical/Mental Response
Response
E.g. Think back to the mindWindows metaphor.
24
Figure 1.10 (p. 16)Design of Davachi et al.
(2003) experiment. There were two parts to this
experiment. The first part, learning, was
followed one day later by a memory experiment.
Note that the participants brain activity was
measured during the learning task using a
technique called functional magnetic resonance
imaging.
25
Figure 1.11 (p. 17)Results for the behavioral
part of the Davachi et al. (2003) experiment.
This graph indicates the relationship between how
the participants related to the stimulus (place
or read) during learning and their performance in
the memory test. This corresponds to
Relationship A in Figure 1.9.
26
Figure 1.12 (p. 18)The results of the
physiological part of the Davachi et al.
experiment. Left The relationship between how
the participants reacted to the stimulus during
learning (place or read) and the physiological
response (Relationship B). Right The
relationship between the physiological response
and the behavioral response (whether the person
recognized or forgot the word) (Relationship C).
27
Information Processing Approach

• Mind as a processor of information
• Input -gt Mental Processes -gt Output
• To understand it, build it

Task
Mind
I
O
28
Think Critically
29
Think Critically

• Beware cognitive myths
• We only use 10 of our brain
• Group brainstorming
• Left vs right hemisphere
• Left is an accountant, right is a hippie
• Phrenology

30
Think Critically

• Beware vacuous Statements
• E.g. (p. 4) the Stroop effect shows that some
  stimuli can affect our behavior by forcing
  themselves on our consciousness, even if we are
  actively trying to ignore them.

31
Think Critically

• Beware old theories
• E.g. Chomskys Poverty of Stimulus argument (p.
  10) has been rebuked recently Perfors,
  Tenenbaum, Regier (2006) have shown that with
  the right approach it is possible to retrieve
  grammar rules from the data available to children

32
Think Critically

• Correlation does not imply causation
• 100 of people who eat pickles die
• Therefore, eating pickles is bad for you

33
Think Critically

• Davachi states that memory is better if the
  perirhinal cortex is activated when the word is
  being learned (p. 18)
• Does this mean that Perirhinal cortex is involved
  in memory?
• Everything is involved in memory
• Is it involved in associative learning?
• Not necessarily. It could be activated during the
  place task for any number of reasons
• Maybe Ss found it amusing to place words, and the
  perirhinal cortex is actually the amusement
  center maybe being amused correlates with better
  memory

34
Think Critically

• Cognition is far from being solved
• Ask questions
• Use your intuition
• Do thought experiments
• Use multiple sources of information
• Think for yourselves
• How would you design the mind?

35
On the brighter side

• This is a young field, but we understand a lot
  about cognition already
• At this point we are already able to predict
• Learning curves for procedural and declarative
  memories
• How forgetting works (interference and decay)
• How some memories can prime other memories
• How cognitive mechanisms interact
• And much much more

36
Questions
37
Next Lecture

• Cognitive Architectures
• Designing the mind
• No homework