PowerPoint-Pr

1
?
Cognitive Psychology Spring 2005 -Discussion
Section-
2
Cognitive functions

• Perception

Emotion Motivation Action

• Attention

• Memory

• Imagery

• Decision-making

• Reasoning, problem-solving

• Language

3

Level of Analysis
4
Functional

Explaining (and predicting) human behavior in
terms of constructs like Attention, Memory,
etc. Processes that are not directly observable,
but defined in terms of their effects. The lawful
nature of behavior allows its prediction Since
this is slightly tautological, Cognitive
Neuroscience has been on the rise, adding a
physiological and structural level of analysis.
5
Electronics

Electricity is an invisible force that we know
about only through the effects it produces. The
exact nature of electricity is not known but the
laws governing electrical phenomena are clearly
understood and defined. We do know that
electricity is a form of energy resulting from
the existence and motion of charged particles
6
Drawbacks

• Simple fundamentals vs. irreducible complexity
• Inherent variability of the phenomena (low vs.
  high)
• Reliability of measurements
• Possible level of invasiveness (technical,
  ethical)

7
Electronics

• We have to work even harder. However, to predict
  the behavior of a specific circuit, no one gains
  much by a quantum mechanic analysis of
  electronics. So no one does that. Measuring
  Voltages, Resistances and Currents is enough.
• Similarly, in order to predict a specific
  behavior its not necessary to invoke the
  activity pattern of neural populations. But it
  ultimately helps in understanding the nature of
  the phenomena.

8

From the lecture
9
Double dissociation

10
Shiffrar
11

Attention
12

Attention as Selection
13
Change blindness
Demos
14
Change blindness
The way to do it?
They confuse demo and study...
15
Logothetis (2003)
16
Popout - Idea

• Some stimuli need attention to process, others
  dont.

• The ones that do not need attention in visual
  search pop out. They are building blocks of
  perception, basic features.

• These supposedly have a representation in an
  early brain area.

17
Basics
18
But (Pomerantz et al.)
19
Popout-Reality

• There are all kinds of slopes for different
  stimulus configurations.

• Sometimes, complex stimuli also pop out. Basic
  features? Not really. Not in early brain area,
  either.

• To date, Popout doesnt explain anything. Needs
  to be explained itself. No a priori prediction of
  popout possible.

20
Summary

• Indispensible for coordinated and goal-directed
  action.

• Hard to study, theoretically complex.

• Many models have been proposed, all of them are
  imperfect at this point.

21

Perception
22
Perception

What we perceive is NOT a exact copy of the
external world, it is a selective RECONSTRUCTION.
It is a MENTAL REPRESENTATION. (of aspects of the
external world)
23
Implications
4 fundamental non-correspondences

1) Things that we perceive might not be actually
present in the environment.
2) Things that are actually present in the
environment might not be perceived (see
Attention examples of last time).
3) Changes in the environment might not result in
changes in perception (example Thresholds).
4) Changes in perception might not result from
changes in the environment.
24
Perception

4) Shepards tables
1) Kanisza triangle
25
(No Transcript)
26
Perception

This allows us to study the assumptions, the
PROCESSING by looking at illusions and how people
perceive them.
27
Perception
A huge brain machinery is devoted to process
visual information alone. At least 30 of the
brain. Together with other perceptual
information Easily 50. This explains how we
can act efficiently on impoverished input
(assumptions). ?Perception appears effortless.

28
Mary Potter
Looks innocent, but raises many issues.
29
Eye movements
30
Retina
31
Saccadic suppression
Assignment Look in the mirror and follow your
eyes as they move around.
32
QALMRI

• Q
• A
• L
• M
• R
• I
• P