TO DISPLAY VIA PROJECTOR:

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PERCEPTION AND ACTION PSYC 209 25 July
2005 Dean Owen Introduction contd
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INFORMATION PROCESSING APPROACH

• The information-processing approach has become
  dominant in cognitive psychology.
• It attempts to analyze cognition into a set of
  steps in which an abstract entity called
  information is processed.
• Information-processing analysis decomposes a
  cognitive task into a set of abstract
  information-processing steps. Anderson,
  2000

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INFORMATION PROCESSING STAGES
Proximal Stimulus
Sensation
Perception
Interpretation
Response Execution
Response Selection
Identification
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OLDE HOMONCULI NEVER DIE

• Modeler about flow chart of boxes representing
  stages in information processing
• Which homunculus tweaks these, we dont
  know. Andreas Daffertshofer
  2003

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THE INTERNAL INFORMATION-PROCESSING MODEL
STORAGE
STILL MORE PROCESSING
RETINAL IMAGE
MORE PROCESSING
CONSCIOUSNESS
PROCESSING
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SUMMARY OF MEDIATIONAL THEORY

• Mediational theories assume that
• ? Sensations have direct contact with
  ..stimulation.
• ? Simulation is impoverished and ..inadequate
  to account for perception.
• ? Perception is a 2nd stage representing
  ..the distal stimulus.
• ? Meaning is associated from memory at ..the
  subsequent recognition stage.

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Hochbergs Atomistic Approach
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THE CONSTRUCTIVIST APPROACH

• Some constructive process occurs within the
  observer that mediates between the physical world
  of objects and events and its perception.
• What we perceive is a mental construction based
  on our cognitive strategies, past experiences,
  biases, expectations, motives, attention,
  etc. Schiffman, 2001

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ATTENTION AS MEDIATION

• We do not and cannot attend to most of the
  available information from the environment.
• Some intevening selection process mediates
  between the input from the environment and our
  awareness.
• What is happening inside the brain when we
  confront an attention-demanding task in which
  multiple stimuli in the retinal image compete for
  attention? Schiffman, 2001

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MEDIATIONAL THEORY

• Perception is a set of processes that actively
  construct mental representations of the world
  from raw, noisy, and incomplete sensory
  signals. Tumblin Ferwerda,
  2001 contd

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MEDIATIONAL THEORY

• Perception is a set of processes that actively
  construct mental representations of the world
  from raw, noisy, and incomplete sensory
  signals. Tumblin Ferwerda,
  2001 contd

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MEDIATIONAL THEORY

• Perception is a set of processes that actively
  construct mental representations of the world
  from raw, noisy, and incomplete sensory
  signals. Tumblin Ferwerda,
  2001 contd

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MEDIATIONAL THEORY

• Perception is a set of processes that actively
  construct mental representations of the world
  from raw, noisy, and incomplete sensory
  signals. Tumblin Ferwerda,
  2001 contd

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MEDIATIONAL THEORY

• Perception is a set of processes that actively
  construct mental representations of the world
  from raw, noisy, and incomplete sensory
  signals. Tumblin Ferwerda,
  2001 contd

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• What if every one of these assumptions is
  incorrect?

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QUESTIONS AND ANSWERSABOUT PERCEIVING

• Why do we perceive?
• To form a representation of the environment.
• To reduce uncertainty about what is there and
  what is happening in order to achieve what is
  desirable and avoid what is undesirable.
• What do we perceive?
• Features colours, forms, depth.
• Events, the layout of the environment, and our
  place in it.
• Affordances edibility, graspability,
  legibility.

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Questions and answers (contd)

• How do we perceive?
• Indirectly by inferring, interpreting,
  estimating, computing, based on impoverished and
  inadequate information.
• Directly by acquiring information about
  affordances from rich and adequate sources.
• When?
• Past, present, future.
• Where?
• Inside the skin, head, brain.
• Inside the environment.

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The Picture on the Retina.

• The immediate cause of our vision is just such a
  mosaic of stimulation as that of a photographic
  plate.
• How can the enormous richness and variety of our
  behavioural environment be aroused by such a mere
  mosaic of light and shade and colour?
• How can such rich effects arise out of such poor
  causes,
• for clearly the dimensions of our
  environmental field are far more numerous than
  those of the mosaic of stimulation?
  Koffka, 1935

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Why do things look as they do?

• K0FFKAS QUESTION

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KOFFKAS ANSWER

• Things look as they because of the field of
  organization to which the proximal stimulus gives
  rise.
• This answer means that we have to study the laws
  of organization.
• Organization is a process
  Koffka, 1935

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GIBSONS ANSWER

• Things look as they do because they appear to
  support the actions that are necessary to achieve
  our goals.
• But we may have to engage in exploratory and/or
  performatory behaviour to determine whether our
  judgment is correct.

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GIBSON'S QUESTIONS

• How do we see the environment around us?
• How do we see its surfaces, their layout, and
  their colours and textures?
• How do we see where we are in the environment?
• How do we see whether or not we are moving and,
  if we are, where we are going?
• How do we see how to do things, to thread a
  needle or drive an automobile?

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GIBSONS DIRECT THEORY

• Perception is anchored to what is in front of the
  eye, not what is on the back of the eye.
• There is no need to represent a scene when the
  scene itself is before you (wysiwyg).
• Information can be common to two or more senses
  (e.g., shape via vision and touch).
  contd

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COMMON SENSE contd

• If buried by an avalanche, it's difficult to tell
  which way is up -- which way to dig yourself out.
  Spit.
• The saliva will run down.
• Dig in the opposite direction.
• If you don't have the energy to spit, just drool.
• However, you will have to feel which way is
  down, rather than see it.

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ANCIENT FUNCTIONALISM

• Aristotle logically distinguished the knowing
  mind (or subject) from the known object, but
  stated that in reality the two were inseparable.
• He described perception as the joint
  actualization of two potentials, the potential of
  the perceiver to sense and the potential of the
  object to be sensed.
• He saw knower and known united in a functional
  interdependency. Lombardo, 1987

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Ecological psychology is functional, therefore
concerned with real- world tasks.
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PARADIGM SHIFT THE UNIT OF ANALYSIS

• A shift in the conceptual foundation of a field
  must be accompanied by a shift in the unit of
  analysis to which researchers attend.
  Knowles Smith, 1981 or 1982

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THE UNIT OF ANALYSIS

• Trying to understand perception by studying only
  neurons is like trying to understand bird flight
  by studying only feathers It just cannot be
  done.
• To understand bird flight, we have to understand
  aerodynamics only then do the structure of
  feathers and the different shapes of birds wings
  make sense. Marr, 1982

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THE ECOSYSTEM
Person
or
Task
Group
Technology
Environment
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THE ECOLOGICAL UNIT OF ANALYSISGibson, 1979

• Locomotion and manipulation, like the movements
  of the eyes are kinds of behavior that cannot be
  reduced to responses.
• Locomotion and manipulation are not triggered by
  stimuli from outside the body, nor are they
  initiated by commands from inside the brain.
• Locomotion and manipulation are neither triggered
  nor commanded but controlled.
  contd

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ECOLOGICAL UNIT OF ANALYSIS contd

• They are constrained, guided, or steered, and
  only in this sense are they ruled or governed.
• And they are controlled not by the brain but by
  information, that is, by seeing oneself in the
  world.
• Control lies in the animal-environment
  system. contd

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ECOLOGICAL FUNCTIONALISM

• Vision is at its simplest when it fulfils its
  ..function.
• Its function is to help the organism cope
  ..with the environment. J.J.
  Gibson, 1979

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Controlled locomotion by a dragon fly is a very
cognitive matter.

• The dragonfly thicket system expresses why it
  is that controlled locomotion is such a
  fundamental form of knowing about.
• To satisfy its intent in the thicket, the
  dragonfly must know where it is, where it can go,
  when it can go, and how it can get
  there. Turvey Shaw,
  1999 contd

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TurveyShaw,1999
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Turvey Shaw,1999
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PRIORITY OF THE WHAT

• The functional psychologist may believe in the
  description of the what coming first before the
  why of its functioning can be understood.
  Boring, 1957

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• Motivated by what?
• Intending to achieve what?
• Intending to avoid what?
• Attending to what?
• Looking for what? Listening for what?
• Feeling, sniffing, tasting for what?
• Detecting, discriminating, recognizing,
  identifying what?
• Acting upon what?

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PERCEPTION DEFINEDby Bruce, Green
Georgeson,(2003), Visual Perception

• If the movement of an animals body is to adapt
  it to its environment, it must be regulated, or
  guided, by the environment.
• For its movement to be regulated by the
  environment, an animal must be able to detect
  structures and events in its surroundings.
• We call this ability perception.

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THE PRIORITY OF PHILOSOPHY

• First you have to have a philosophy that matches
  the problem domain to guide theory development.
• Realism Material objects exist (have a reality)
  apart from awareness of them.
• Ecological realism A reality emerging from
  interaction with the environment and feedback
  from those interactions.

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• END
• 25-7-05