Introduction, philosophy, psychology and neuroscience of perception

Question 1

Define sensation

Answer 1

awareness of a physical stimulus through the senses

Question 2

define perception

Answer 2

the ability to apprehend, or become aware of something through the senses

Question 3

Difference between sensation and perception?

Answer 3

received sensory data VS interpreting sensory data

Question 4

Psychological relationship of sensation and perception

Answer 4

Perception brings our knowledge of the world to organise the raw data of sensation

Question 5

What are the neural requirements for sensation and perception?

Answer 5

• sensory receptors -> transduce signals
• axonal projections to CNS -> stimulation
• central pathways through CNS
• leading to specific sensory area of cerebral cortex (primary visual cortex receives input)
• on to ‘higher’ association areas of cortex

Question 6

Perception via the senses?

Answer 6

1. Direct perception (naive realism)
2. Indirect realism: we cannot perceive objects directly
   - We experience sensations perceptions, which we assume are reliably due to the real world
   
   • Physics (sound, light, mechanical forces)
   • sensory detectors
   • CNS processing
     - Perceiving: constructing a mental representation of it

Question 7

Representational model of the mind

Answer 7

• Outer world - physics: mass, energy, molecules
• Inner world - mental states: sights, sounds, etc

Question 8

What about the problem of scepticism?

Answer 8

• Possibility of radical skepticism?
• Trusting our sense data? Dreaming?

Question 9

The mind-body problem

Answer 9

• Dualism: there is mind-stuff and there is physical stuff and they are fundamentally different kinds
• Materialism: also physicalism, there is no reality but physical reality

Question 10

Problem of perception?

Answer 10

• Reliability of perception = philosophical problems
• does all knowledge come from sensory experience?

Question 11

Origins of knowledge

Answer 11

Empiricism vs Nativism

Question 12

Empiricism (blank state):

Answer 12

• all knowledge comes from sensory experience, ordered by learning associations between experiences
• implies a passive view of perception

Question 13

Nativism:

Answer 13

• the way we organise experience depends on innate knowledge
• the perceiver is actively involved in interpreting the sensory input

Question 14

What does perception depend on?

Answer 14

• Implicit knowledge
• assumption that the world is 3D
• Helmholtz (1867): perception as unconscious inference

Question 15

What is perceptual processing?

Answer 15

There are 2 types; bottom-up and top-down

Question 16

Bottom-up

Answer 16

from sensory input alone (feedforward in neural terms)

Question 17

Top-down

Answer 17

processing of sensory input is influenced by other cognitive factors, memory, expectation, attention, implicit knowledge (feedback in neural terms)