Theories of Perception (AQA GCSE Psychology): Flashcards

Motion parallax is a monocular depth cue which occurs when the observer is moving — on foot, by bike, in a car or on a train.

Near objects appear to move fast and in the opposite direction to the observer, like fence posts past a train window. Distant objects move slowly and in the same direction, like hills on the horizon.

Optic flow is where, as we move forward, the whole visual scene appears to flow outwards from the point we are heading towards, which itself stays still.

It gives direct information about the plane’s speed, its angle of approach and its distance from the runway. The point of the runway the plane is heading towards stays still while the ground streams past either side.

It has high ecological validity. Unlike research using 2-D illusions in a lab, Gibson studied perception while people moved through real 3-D environments, which is how perception normally operates.

It cannot easily explain visual illusions. If perception were direct and accurate, illusions such as the Müller-Lyer should not occur — suggesting the brain is interpreting information, as Gregory argued.

Hudson found that people from cultures with little exposure to pictures interpreted depth cues in drawings differently, suggesting perception is at least partly learned.

Gregory’s constructivist theory claims perception is constructed by the brain from two sources: the information coming in from the senses, and past experience stored in memory.

Sensory information on its own is often incomplete or ambiguous, so the brain goes beyond it using what it has learned before — seeing a curved fin and thinking ‘shark!’.

False.

Perception is an active process — the brain is constantly forming and testing hypotheses about what it is seeing.

False.

It is top-down: perception starts with stored knowledge and expectations, which are then used to interpret the sensory data — the opposite of Gibson’s approach.

A man who had been blind from infancy and had his sight restored by a corneal graft at the age of 52.

He could recognise by sight objects he already knew well by touch — he could tell the time from a wall clock, having handled a watch with raised hands. He could also walk a corridor and judge the size of familiar objects such as a bus.

He could not judge depth and distance — he thought he could lower himself to the ground from a window 30–40 feet up. He found crossing the road frightening, and struggled to recognise objects he had never touched.

SB never fully adjusted to sight, became withdrawn and died around two years later.

The abilities SB had were those he could build from past touch experience; those he lacked were the ones that had to be learned visually in childhood. This supports perception being constructed from experience.

SB is a single, highly unusual case, so his experience cannot be generalised to how perception normally develops.

Because past experience has taught us what they mean — for example, converging lines mean distance.

A mistaken hypothesis is where the brain applies a hypothesis based on past experience to an image where it does not fit — in the Ponzo illusion it hypothesises that the upper bar is further away, so perceives it as longer.

It explains visual illusions such as the Ponzo and Müller-Lyer as mistaken hypotheses based on misapplied depth cues — something Gibson’s direct theory struggles to do.

Hudson found that people with little experience of pictures interpreted depth cues in drawings differently from those with more experience, suggesting perception is shaped by learning.

Some perception appears innate: Gibson & Walk (1960) found most babies refused an apparent drop, and Fantz (1961) found newborns prefer face-like patterns — hard to explain if perception is entirely learned.

If perception were hypothesis-testing, the Müller-Lyer should stop working once we have measured the lines — but it does not, suggesting something other than learned inference is involved.