Module 17 - basic concepts of sensation and perception

Question 1

sensation

Answer 1

• process of receiving sensory information
• a stimulus (energy) stimulates sensory receptors
• energy is transduced into electrochemical energy and delivered to the brain
  
  • energy transduced in the form of action potentials

Question 2

two types of processing

Answer 2

1. top-down processing
   - uses other information
   - prior expectations, knowledge, etc.
2. bottom-up processing
   - uses only the raw sensations

Question 3

Absolute threshold

Answer 3

• theoretical minimum intensity of a stimulus needed to be detectable
• not typically a consistent minimum amount, so its often measured as the intensity that’s detectable some percentage of the time (50%)

Question 4

difference threshold (JND)

Answer 4

• just noticeable difference
• theoretical minimum change in intensity of stimulus needed to be detectable
• not typically a consistent minimum amount, so its often measured as the change that’s detectable some percentage of the time (50%)

Question 5

stimulus detection probability

Answer 5

• probability of detecting a stimulus (portion of stimuli detected) is typically an s-shaped function of the stimulus intensity

Question 6

Weber’s Law

Answer 6

• the JND for given type of stimulus is constant proportion of stimulus intensity
  
  • not a constant amount
  • ex: if you need to add 1lb to a 10lb weight for the JND, you need to add 10lb to a 100lb weight for the difference to be noticeable
• some stimuli follow approximately but not all

Question 7

sensory adaptation

Answer 7

• reduced sensitivity resulting from constant stimulation
  
  • ex: if you stop hearing an air conditioner after a while
• unchanging stimuli aren’t typically important
• perceive the world not exactly as is, but in a way that tends to be useful to us
• actually sense the stimuli less