Download MIND: The Cognitive Side of Mind and Brain

MIND: The Cognitive Side of
Mind and Brain
 “… the mind is not the brain, but what
the brain does…” (Pinker, 1997)
COGNITIVE PSYCHOLOGY
emerged late 1960s:
 The scientific study of higher mental
processes, from perception and action
through memory, language, thinking, and
problem solving. These mental activities
involve the processing of information.
COGNITIVE PSYCHOLOGY
 GOAL: To understand how the mind
works
 METHODS: Based on scientific
experimentation
 EXPLANATION: Focuses on the nature
of mental representations and the
processes that operate on them
INFORMATION
PROCESSING METAPHOR:
 Both brain and computers process
information
 Information (knowledge, representation,
symbols) is independent of the physical
medium
COGNITIVE SCIENCE:
Interdisciplinary study of the
mind emerged late 1970s
 Cognitive Psychology
 Artificial Intelligence
 Neuroscience
 Linguistics
 Philosophy
 Anthropology
NEUROSCIENCE
 GOAL: To understand how the brain
works
 METHODS: Based on scientific
experimentation
 EXPLANATION: Focuses on nervous
system function and performance
Cognitive Psychology and
Neuroscience Together
 Initially, interest, but little direct contact


Two sides of a coin; burning a candle at
both ends
Very difficult to map cognitive level of
explanation onto brain
 Today, the cumulative advances in our
scientific knowledge and technology
have opened new possibilities for
collaboration.
Cognitive Psychology
provides:
 Logical analysis of the mental structures and
processes presumed to be involved in the
performance of many tasks (task analysis).
 This analysis used to develop cognitive tasks to
assess aspects of perception, attention, and
memory.
 Models of mental structures and processes of
human perception, attention, memory, etc.
based on data obtained from solid experimental
procedures
Cognitive Psychology and
Neuroscience:
 1990s: Neuroimaging studies
demonstrate activation of specific brain
areas when people perform classic
cognitive tasks.
 2000s: Some neuroimaging studies help
distinguish between alternative
theoretical accounts of cognitive
performance.
COURSE OVERVIEW
 Visual Perception: We are visual
animals
 Visual Attention: We select some, but not
all, stimuli for processing
 Visual Awareness: We are conscious of
some, but not all, experiences
PERCEPTION
 Ramachandran video:

Phantom limb, blind sight, unilateral
neglect, Capgras syndromes reveal that
visual perception is not the same as
sensation.
IMPOSSIBLE OBJECTS
 Objects to right
initially look like
coherent objects, but
they are not
physically possible.
 Vision does not
simply register what
is present. It actively
constructs percepts
VISUAL PERCEPTION
 ACTIVE INTERPRETATION of sensory
input
 “We perceive the world through the filter
of our knowledge and experience”
Consider THIS ROOM from
the perspective of:
 Our eyes
 Pre-school child Moose
 Moose
VISUAL PERCEPTION
 GOAL: To understand the 3D structure of
the world around us by identifying:



What objects are out there
Where they are located
What they are doing
Recognizing Things
 Single Objects:

My mug in different places, orientations,
lighting conditions changes location, size.
 Letters & Words:

Type fonts, all other above variations.
 Faces:

Different views (frontal, side), all other
above variations
Three Levels of Perceptual
Identification
 Superordinate: Fruit
 Entry level: Apple
 Subordinate: Granny Smith Apple
 Sensory input identified at the level
appropriate for the task at hand: If we
want to eat an apple, we identify the
object as an apple, not as a fruit or a
Granny Smith apple.
Stages of Processing:
A Generic Symbolic Model
Stages of Processing
 Each stage (i.e., box)
is a different level of
processing.
 Two classes of
processes:
Bottom-up (datadriven, sensorydriven)
Top-down
(conceptually driven)
Dimensional analysis
 A large set of
“detectors” operating
in parallel to code
edges, color,
movement (covered
in lectures on
Chapters 1 and 2).
 Analyzers operate in
parallel.
Figure Construction Mechanism
 Organizes the image
by segmenting
(parsing) it into parts
and grouping the
parts appropriately.
 How do we know
which parts go
together in the figure
to the right?
Figure Construction Mechanism
 Organizes image by
binding attributes
together
 Gestalt Principles of
Grouping
 Multiple glimpses,
binocular disparity
 Shape from shading,
depth from texture
Figure Construction Mechanism
 Organizes image by
determining what is
figure (that which we
attend to) and what
is ground.
 Ambiguous figures:
two equally good
figures constructed,
as in the Necker
cube.
Perceptual Representation
and Comparison Mechanism
 Perceptual Representation:
The organized percept,
ready for identification.
 The perceptual
representation is compared
to our stored shape
knowledge (i.e., shape
representations) by the
Comparison Mechanism.
Top-down Influences
 Local context and
our expectations
influence perception.
 We do not yet know
how early in visual
processing top-down
influences of context
operate.
Definitions
 Bottom-up processing
(BU): The sequence of
mental events is largely
determined by the pattern
of incoming information.
 Top-down processing
(TD): The sequence of
mental events is
influenced by our
knowledge and
expectations.
 In perception:


processing initially
starts with sensation
and BU processing.
thereafter, BU and TD
processing occur
simultaneously.
VISUAL PERCEPTION
 GOAL: To understand the 3D structure of
the world around us by identifying what
objects are out there, where they are
located, and what they are doing.
What’s next?
 Dr. Carolyn Harley completes coverage
of Chapters 1 & 2


Chapter 1: Early Vision: Retina and
Retinal Ganglion Cells, LGN, Primary
Visual Cortex
Chapter 2: From Local to Global Image
Recognition: Color, Motion, Image
Segmentation, Two Cortical Systems