Sensation and Perception

Question 1

What is perpetual dysfunction?

Answer 1

• disability to interpret sensory information
• visual agnosia - inability to recognize visual objects
• prosopagnosia - inability to recognize face identities

Question 2

Sensation VS Perception

Answer 2

• sensation: the stimulation of sense organs
• perception: selection, organization and interpretation of sensory inputs

Question 3

Describe the features of the retina

Answer 3

• cone cells: daylight/color vision (acuity)
• rod cells: night/peripheral vision (sensitivity)
• fovea: tiny spot at the centre of the retina with only cones, greatest acuity

Question 4

Describe dark and light adaptation

Answer 4

• Dark
  
  • Eyes become more sensitive to light in low illumination
  • Less light required to see
• Light
  
  • Eyes become less sensitive to light in high illumination
  • Improvesvisual acuity
• Adaptation due to changes in biochemical composition of cones and rods

Question 5

Define visual field

Answer 5

The area in space captured by the retina, ie the area that we see

Question 6

Define retina and visual cortex in terms of the visual pathway

Answer 6

• Retina: sheet of neurons that process images from the visual field
• Visual cortex: sheet of neurons that process images from the retina

Question 7

Describe the two pathways of visual perception

Answer 7

• dorsal where pathway: position of objects
• ventral what pathway: identity of objects

Question 8

Explain depth perception

Answer 8

• interpretation of visual cues indicating clues about distance
• monocular: based on image in either eye alone
  
  • pictorial depth cues in a flat picture
  • eg texture gradient, relative size, light and shadow
• binocular: based on differing views of both eyes
  
  • retinal disparity occurs when the right and left eyes see different images (close objects)

Question 9

Describe Hubel and Wiesel’s study of neurons in the primary visual cortex

Answer 9

• each visual cortex neuron receives info from a close group of retinal cells
• Feature Detectors: neurons responding selectively to specific features of complex stimuli, eg lines, edges

Question 10

Describe feature analysis

Answer 10

Detecting simple, elemental features and assembling them into a more complex form

Question 11

Bottom-up processing VS top-down processing

Answer 11

• Bottom-up
  
  • progression from individual elements to the whole
• Top-down
  
  • progression from the whole to individual elements