Perception

Question 1

Define perception

Answer 1

The organisation, identification and interpretation of a sensation in order to form a mental representation

Question 2

Define sensation

Answer 2

Simple awareness due to the stimulation of a sense organs

Question 3

Where are receptor cells found?

Answer 3

Organised into sensory organs or distributed through tissues such as skin and muscle

Question 4

Describe the relationship between perception and receptor cells

Answer 4

• Perception depends on effects of external energy on the activity of specialised nerve cells
• Receptor cells transduce external injury into electrical signals, transmitted on to other nerve cells

Question 5

Define synaesthesia

Answer 5

The perception experience of one sense that is evoked by another sense. Simulation of one sensory pathways leads to automatic, involuntary experiences in a second pathway

Question 6

Synaesthesisa has a strong hereditary factor. Which chromosome is it linked with

Answer 6

X chromosome

Question 7

Define absolute threshold

Answer 7

-Describes the relationship between the physical intensity of a stimuli and whether it is perceived or not. Minimum intensity needed to just barely detect a stimulus

Question 8

Describe finding the absolute threshold

Answer 8

Observer presented with stimulus varying intensity. Each trial responds yes or no if they can detect it. E.g hearing test- absolute threshold as the loudness required for the listener to say they heard the tone in 50% of trials

Question 9

What is the just noticeable difference?

Answer 9

The absolute threshold is useful for assessing how sensitive we are to faint stimuli but most everyday perception involves detecting stimuli well above absolute. JND is a way of measuring this different threshold. It is the minimal change in a stimulus that can just barely be detected

Question 10

Describe finding the just noticeable difference

Answer 10

Observer presented repeatedly with a reference stimuli (fixed intensity) and a comparison stimuli (varies). Responds by saying whether the comparison stimulus appears more or less intense that the reference

Question 11

What is Fechner’s law?

Answer 11

Perceived intensity of a stimulus increases in proportion to the logarithm of its physical intensity

Question 12

Describe signal detection theory

Answer 12

Treats a stimulis as a signal that needs to be detected against a background fog noise. Noise is caused by random fluctuations in receptor cells and other neurons

Question 13

Define modalities

Answer 13

Sensory brain regions that process different components of the perceptual world

Question 14

Define transduction

Answer 14

What takes place when many sensors in the body convert physical signals from the environment into neural signals sent to the central nervous system. E.g light reflected from surfaces provide the eyes with information about the shape, colour, position of objects

Question 15

Define psychophysics

Answer 15

Methods that measure the strength of a stimulus and the observers sensitivity to that stimulus.
Developed by Fechner

Question 16

Define Weber’s law

Answer 16

The just noticeable difference of a stimulus is a constant proportion despite variations in intensity

Question 17

Define signal detection theory

Answer 17

An observation that the response to a stimulus depends on a person’s sensitivity to the stimulus in the presence of noise and on a person’s response criterion

Question 18

Define D prime

Answer 18

A statistic that gives a relatively pure measure of the observers sensitivity or ability to detect signals

Question 19

Define sensory adaptation

Answer 19

Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions

Question 20

What is the retina?

Answer 20

Light sensitive tissue lining the back of the eyeball (light focused on the retina)

Question 21

Define accommodation

Answer 21

The process by which the eye maintains a clear imagine on the retina

Question 22

Define visual acuity

Answer 22

The ability to see fine detail

Question 23

Define cones

Answer 23

Photoreceptors that detect colour, operate under normal daylight conditions and allow us to focus on fine details

Question 24

Define rods

Answer 24

Photoreceptors that become active only under low light conditions for night vision

Question 25

Describe the location of photoreceptors

Answer 25

In the retina. About 120 million rods are distributed around each retina except in the very centre, the fovea.- an area of the retina where vision is the clearest. The absence of rods in the fovea decreases the sharpness of vision in reduced light but it can be overcome. Each retina only contains about 6 million cones which are densely packed in the fovea

Question 26

Are rods or cones more sensitive?

Answer 26

Rods

Question 27

Define blind spot

Answer 27

An area of the retina that contains neither cones or rods and therefore has no mechanism to detect light

Question 28

Define receptive field

Answer 28

The region of the sensory surface that, when stimulated, causes a change in the firing rate of that neuron

Question 29

Define tropographic visual organisation

Answer 29

Adjacent neurons process adjacent portions of the visual field

Question 30

What is area v1?

Answer 30

The initial processing region of the primary visual cortex

Question 31

What is visual form agnosia?

Answer 31

The inability to recognise objects by sight

Question 32

What is the binding problem?

Answer 32

How features are linked together so that we see unified objects in our visual field

Question 33

Define illusory conjunction

Answer 33

A perceptual mistake where features from multiple objects are incorrectly combined

Question 34

Define feature integration theory

Answer 34

A theory that proposes that attention binds individual features together to comprise a composite stimulus

Question 35

Define modularisation

Answer 35

the process of relatively encapsulated function

Question 36

Define perpetual constancy

Answer 36

A perceptual principle stating that even as aspects of sensory signals change, perception remains consistence

Question 37

What are monocular depth cues?

Answer 37

Aspects of a scene that yield information about depth when viewed with only one eye