Visual Perception

Question 1

what is the absolute threshold?

Answer 1

the minimum amount of stimuli energy needed for an observer to perceive a stimulus, in ideal conditions

Question 2

what are the stages of vision?

Answer 2

• involves two stages: sensation and perception

1. SENSATION → reception, transduction, transmission
2. PERCEPTION → Selection, Organisation, interpretation

Question 3

what is sensation?

Answer 3

• name given to the process of our sensory organs collecting visual stimuli
• occurs in three stages
  1. Reception
  2. Transduction
  3. Transmission

Question 4

what is the 1st stage of sensation and what are the steps?

Answer 4

Reception:

• light energy enters the eye
• light first enters through the cornea, the thin tissue overing the eye, and then passes through the pupil in the middle of the eye
• photo receptors = detect light in external environment
• rodes = detect black and white, intensity of light
• Cones = detect colour variation of light, need bright light to operate properly
• live waves between 360-720 nanometers from the visible spectrum. The electromagnetic spectrum.
• The energy that enables us to see is called light energy

Question 5

what is the 2nd stage of sensation and what are the steps?

Answer 5

Transduction:
- conversion of light energy into electrochemical nerve impulses in the retina using the rods and cones

• the light energy needs to be converted so it can travel along the optic nerve into the occipital lobes in the brain

Question 6

what is the 3rd stage of sensation and what are the steps?

Answer 6

Transmission:

• occurs when the nerve impulses are sent to the primary visual cortex in occipital lobe

Question 7

what is the 1st stage of perception and what are the steps?

Answer 7

Selection:

• involves cells called feature detectors found in optic nerve and primary visual

Question 8

what is the 2nd stage of perception and what are the steps?

Answer 8

Organisation:

• our visual cortex then organises this information using various perception principles, to identify the object and its position

Question 9

what is the 3rd stage of perception and what are the steps?

Answer 9

interpretation:

• the visual stimuli is given meaning
• information → temporal lobe for interpretation where the object being perceived can be compared to stored memory and identified
• The information is also sent to the parietal lobe, so the object can be localised in relation to us and our visual field.