(Cognitive) Perception

Question 1

What is sensation

Answer 1

The ability of the sense organs to detect various forms of energy (light and sound waves)

To sense

Question 2

What is perception

Answer 2

The analysis of this sensory information to describe the surrounding environment.

To make sense of

Question 3

Top-down approaches

Answer 3

our mind, prior knowledge, expectations, etc, driving the world around us, with a little input from sensations/the world around us.

Question 4

Bottom-up approaches

Answer 4

emphasises the primacy of sensation and environment, with maybe a little bit of the mind steering.

Question 5

The Ecological Approach
Gibson, 1940s+
Bottom-up

Answer 5

The basics of this approach are that we should focus on real environments, not 2D stimuli. All the necessary information can be ‘picked up’ from the environment. NO NEED FOR MENTAL PROCESSES/PREVIOUS EXPERIENCE.

Question 6

Gibson based this off his experience of…

Answer 6

training pilots in WW11, when he found that performance tests using pictures didn’t relate to performance (Gibson, 1947).

Question 7

Ambient optic array

Answer 7

Light reflects off surfaces before reaching the eyes. Ambient optic array = the structure/pattern of this light. Information in optic array changes as you move through it.

Question 8

Invariants

Answer 8

Its argued that ‘invariants’ within the optic array facilitated perception. A range of different invariants within the optic array have been identified that are characteristics of perception in real environments.

Question 9

Affordances

Gibson (1979)

Answer 9

He suggested that the patterns of light directly ‘afforded’ the use of objects - perception and action are directly linked. I.e a banana ‘affords’ being eaten.
What he suggests doesn’t happen is that we recognise that it is a banana, and then process what to do with it (using memory for example). This is controversial because it discounts any knowledge or expectations on the part of the individual.

Question 10

Constructivist Approach
Richard Gregory (1997)
Top-down

Answer 10

Two key principles:
-Information from sensations are incomplete and imperfect.
-Therefore, perceptual knowledge needed to unconsciously ‘construct’ our perceptions.

i.e. Hollow face illusion

Richard Gregory - “…perceptions are regarded as similar to predictive hypotheses in science but are psychologically projected into external space and accepted as our most immediate reality.”

Question 11

Hollow Face Illusion

Answer 11

First brought into the psychological literature by Gregory 1970 and it’s a powerful demonstration of the importance of knowledge, and as Stephen Fry explained to us it the fact that we’ve been experiencing since infancy, real faces. So we are not equipped to know what to do with an inside out face, and so based on that prior knowledge, we percieve it as projecting towards us (convex), as this is how faces are experienced. Despite knowing that what we are seeing is hollow (concave.)

Question 12

Kanisza illusion
(Kanisza, 1955)

Answer 12

The size shape and colour of this occluding (being in the front of) surface are determined by the context. Our mind fills out the shape that’s not there.

Question 13

Experimental evidence for top-down approach

Answer 13

Two examples are the configural superiority effect and the object superiority effect. Both involve participants identifying a perceptual property of a display.

Question 14

Object superiority effect

First identified by Weisstein & Harris (1974)

Answer 14

Perceptual properties of a display are picked out faster if part of an object. Participants had to identify which target line was being displayed out of a,b,c or d. If the line was presented as part of a plausible cube-like object (albeit unfamiliar and basic) participants were more accurate. This was in comparison to random non-object like displays (participants still most accurate if lines presented in isolation). This finding is inconsistent with context not playing a role.

Question 15

Configural superiority effect
Pomerantz et al. (1977)

Answer 15

A related but distinct effect. These demonstrations are more concerned with context aiding perception, regardless of whether it forms a plausible object. I.e., Pomerantz et al. (1977) had pps identify the odd one out in displays. Participants were faster when there was a ‘good’ context compared to a poor context. ‘Good’ here refers to the context making the target line discriminable (i.e. distinctive).

Question 16

Object vs Configural

Answer 16

Both suggest that we’re better at perceiving things that are in a coherant context.
Object superiority effects argue for the influence of object knowledge (relatively higher order knowledge).
Whilst configural superiority effects suggest that being ‘object-like’ is less important than the context providing distinctive information (lower order).

Question 17

Gestalt Laws of organisation

Answer 17

‘Gestalt’ is associated with a group of German psychologists in the turn of the 20th century.
Gestalt = humans percieved things as wholes rather than individual parts.
Wertheimer (1923) proposed 5 Gestals laws of organisation.

Question 18

Proximity

Answer 18

Elements that are close together are seen to group together.

Question 19

Similarity

Answer 19

Elements that are similar are perceived as grouping together.
An applied example is proximity and similarity playing a role in camouflage.

Question 20

Closure

Answer 20

We ‘fill in’ gaps to see whole or complete objects.

Question 21

Good continuation

Answer 21

No perceived break in continuation across intersections.

Question 22

Common Fate

Answer 22

Objects moving the same direction and speed are percieved as a group.

Question 23

Limitations of these principles

Answer 23

Too simplistic
Mostly descriptive, lacks predictive power
Captures 2D displays, but not as easy to apply to 3D

Question 24

Contsraints