Introduction to Perception

1
Introduction to Perception
2
The perceptual process. The steps in this
process are arranged in a circle to emphasize the
fact that the process is dynamic and continually
changing. Blue arrows point to stimuli green to
processing red to perceptual responses. Arrows
A, B, and C indicate three important
relationships that researchers measure.
3
The Perceptual Process

• Environmental stimuli
• All available stimuli for an observer
• Attended stimuli
• Stimuli that are the point of focus for the
  observer
• Stimulus on the receptors
• Image of stimulus on receptor cells

4

• (a) We take the woods as the starting point for
  our description of the perceptual process.
  Everything in the woods is the environmental
  stimulus. (b) Ellen focuses on the moth, which
  becomes the attended stimulus.

5
The Perceptual Process - continued

• Transduction
• Change from environmental energy to electrical
  energy in the nervous system
• Neural processing
• Interconnected neurons that propagate the
  electrical signal from receptor cells throughout
  the brain

6

• (a) An image of the moth is formed on Ellens
  retina. (b) Transduction occurs when the
  receptors create electrical energy in response to
  the light. (c) This electrical energy is
  processed through networks of neurons

7
The Perceptual Process- continued

• Perception
• Conscious sensory experience
• Recognition
• Ability to place objects in categories that
  provide meaning
• Action
• Motor activities that occur in reference to the
  perceived and recognized object

8

• (a) Ellen has conscious perception of the moth.
  (b) She recognizes the moth. (c) She takes
  action by walking toward the tree to get a better
  view.

9

• The perceptual process. The steps in this
  process are arranged in a circle to emphasize the
  fact that the process is dynamic and continually
  changing. Blue point to stimuli green to
  processing red to perceptual responses. Arrows
  A, B, and C indicate three important
  relationships that researchers measure.

10
Two Interacting Aspects of Perception

• Bottom-up processing
• Processing based on incoming stimuli from the
  environment
• Also called data-based processing
• Top-down processing
• Processing based on the perceivers previous
  knowledge
• Also called knowledge-based processing

11

• Perception is determined by an interaction
  between bottom-up processing, which starts with
  the image of the receptors, and top-down
  processing, which brings the observers knowledge
  into play. In this example, (a) the image of the
  moth on Ellens retina initiates bottom-up
  processing, and (b) her prior knowledge of moths
  contributes to top-down processing.

12
Approaches to the Study of Perception

• Levels of Analysis
• Observing perceptual processes at different
  scales
• Psychophysical level - the stimulus-perception
  relationship
• Physiological level - the stimulus-physiology
  relationship
• These levels are interconnected and communicate
  with one another

13

• Experiments that measure the relationships
  indicated by the arrows in figure 1.1. (A)
  Stimulus-perception Two colored patches are
  judged to be different. (B) Stimulus-physiology
  A colored light generates a neural response in
  the cats cortex. (C) Physiology-perception
  Brain activity is monitored as a person indicates
  what he is seeing.

14

• Levels of analysis in the study of perception

15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)