Sensation & perception

Question 1

what is perrception?

Answer 1

process of acquiring knowledge about environmental objects or events via the senses

Question 2

perceptual process is often..

Answer 2

broken down into 2 stages:

sensation: process of transforming physical stimuli to electrical signals
perception: process of interpreting these signals for conscious awareness and for action

Question 3

sensation

Answer 3

process of transforming physical stimuli to electrical signals

• energy from physical stimuli in the environment stimulates sensory receptors
• converted to neural impulses, which are sent to brain

Question 4

perception

Answer 4

process of interpreting these signals for conscious awareness and for action

Question 5

perceptual process using tennis examples

Answer 5

stimuli; distal and proximal

• > sensation: conversion to neural signals which are sent to the brain
• > perception: signal processing and interpretation

Question 6

difference between 2 different types of stimuli

Answer 6

Distal stimuli = objects in the world e.g. ball hitting racket
Proximal stimuli = refers to energy e.g. light from sun reflecting off opponent (vision) and sound waves

Question 7

what is perception for?

Answer 7

has evolved to aid survival and reproduction
- help us seek out desirable objects and avoid dangerous ones

• some species sense energies that humans cannot e.g. reindeer directly perceive UV so break camo

Question 8

different sense

Answer 8

• Somatosensory perception (touch)
• visual perception
• gustatory perception (taste)
• auditory perception
• olfactory perception (smell)
• Proprioception (body position and movement)
• Nociception (pain)
• Themoception (temperature)

Question 9

is perception veridical?

Answer 9

yes as senses would not evolve if they did not provide accurate information of the world
- however, perception is not a clear window as we don’t directly perceive stimuli we have to go through perceptual process

Question 10

define illusions

Answer 10

situations in which perception differs from reality

- in some illusions our perception of objects is systematically distorted

Question 11

examples of illusions :(

Answer 11

• the lilac chase

- the hermann grid illusions

Question 12

Ambiguous figures

Answer 12

A type of illusion which are images that can give rise to 2 or more distinct perceptions

• Our perceptions are rarely ambiguous as our brains always deliver a perception thats not amibguous
• also referred to as bistable images

Question 13

examples of ambiguous figures

Answer 13

• old/young lady
• dress
• duck rabbit

Question 14

Ambiguous sounds

Answer 14

can also give rise to multiple bistable and stable perceptions
- Auditory stream segregation

Question 15

impossible objects

Answer 15

= things that we perceive and know that can’t exist in the physical world

• sometimes sensory input is interpreted by the brain as representing objects or scenarios that are physically impossible e.g. penrose triangle, endless stairs, shepard scale illusion

Question 16

Top down process

Answer 16

= pre existing knowlegde

• use knowledge about the strutuce of the world to influence perception
• AKA conceptually driven processes

Question 17

bottom up process

Answer 17

= info from senses

• take information from senses and make judgements about the nature of the world solely based on this info
• AKA data driven processes

Question 18

top down and bottom up processes

Answer 18

both important as perception is frequently modified by knowledge but knowledge can always override perception
- some theories focus on one component more than the other

Question 19

constructivist theories of perception

Answer 19

Emphasise top down processing (knowledge)

• Helmholtz (1821-1894) argued brain is trying to make the best guess
• popularised by gregory (1923-2010) -‘perception.. best interpretation of the available data’

According to this approach many illusions are better described as rational references rather than perceptual errors

e. g. ponzo illusion
- hollow mask illusion

Question 20

direct theories of perception

Answer 20

Emphasise bottom up processing (senses)

• James Gibson (1904-1974) argued constructivist approach underestimated richness of sensory evidence
• The perceiver is not a passive observer but interacts with the environment which is key to picking up useful info

Question 21

modern approach - information processing paradigm

Answer 21

Stimuli (sensory input) ->
physiology (neural representations & processes) convert physical stimulus in neural code and process it ->
perception and action (output) judgements and actions

Question 22

3 key scientific approaches

Answer 22

1. psychophysics
2. neurophysciology
3. psychophysiology & brain imaging/ stimulation

Question 23

psychophysics

Answer 23

measure relationship between stimulus and perception (no physiology)

• manipulate stimulus and see how peoples perceptions change

Question 24

neurophysciology

Answer 24

measure relationship between a stimulus and the physiological response (no perception)

• manipulate stimulus and see what happens to responses of neurons in brain

Question 25

psychophysiology & brain imaging/ stimulation

Answer 25

measure relationship between physiological responses and perception (no stimuli)

• Try and relate whats happening in the brain through functional imaging to what people are perceiving and doing