W1 - Intro To S&P ✅

Question 1

What are the stages in the perceptual process?

Answer 1

1. Distal stimulus: physical object
2. Proximal stimulus: representation of distal stimulus from each sense receiving information from different stimulus (e.g. eye - light, ear - sound wave)
3. Receptor processes: transduction from stimulus to electrical signal for nerve cells
4. Neural processing: electrical signal being transmtitted between neurons
5. Perception: conscious sensory experience (mental representation based on sensory info)
6. Recognition: categorising object
   -> distinction between 5 & 6 proven by visual form agnosia - inability to identify object but can describe it
7. Action: movement in reacting to the stimulus

(5,6,7 are interactive and influenced by knowledge -> top-down processing)

Question 2

Why do we need top-down processing in perception?

Answer 2

Simplifying the complex perceptual process

Using contexts, assumptions, and memories to “understand” the sensory information and know what to do with it

Question 3

What are 2 approaches to study perception?

Answer 3

Physiological:
- Studying anatomy
- Recording brain activity (e.g. single cell recording, neuro-imaging - EEG, fMRI, PET)
- Micro-stimulation
- Study brain damage (lesions) & TMS (disrupt brain activity to study subsequent behaviours)

Psychophysical: relationship between real stimulus and perceived stimulus
- Identifying thresholds:
1. Absolute (detection)
2. Difference (discrimination)

Question 4

How to measure absolute and difference thresholds?

Answer 4

1. Absolute: constant altering of a stimulus intensity until detection is possible
2. Difference: proportional addition to baseline stimulus until one can tell the difference

Common technique: 2 forced choice (e.g. A or B has stimulus)
-> plotted the answers into graph
=> absolute AND difference thresholds are the levels that give 75% correct performance