Perception

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Gilchrist and Nesberg aim

Gilchrist and Nesberg aim

Gilchrist and Nesberg aimed to find out if food deprivation affects the perception of pictures of food.

Gilchrist and Nesberg Method

Two groups of students: one group deprived of food for 20 hours and a control group (not hungry). Students were shown four slides, each one showing a meal. The slide was displayed for 15 seconds. The picture was shown again, but dimmer, and participants had to adjust the lighting to make it look the same as it did before.

Gilchrist and Nesberg Results

Participants perceived the food as brighter the longer they were deprived of food. The control group (who were not deprived of food) didn't perceive the food as brighter.

Gilchrist and Nesberg Conclusion

Being deprived of food increased perceptual sensitivity. This shows that hunger is a motivating factor that affects the way food-related pictures are perceived.

Bruner and Minturn study aim

Bruner and Minturn aimed to find out whether an ambiguous figure was seen differently if the context of the figure was changed.

Bruner and Minturn Method

An independent groups design was used where participants were either presented with a sequence of letters or a sequence of numbers with the same ambiguous figure in the middle. The ambiguous figure could be seen as either the letter B or as the number 13. Participants had to report and also draw what they saw.

Bruner and Minturn Results

Those who saw a sequence of letters were more likely to report the figure as being the letter B and tended to draw a 'B'. If shown numbers they were more likely to say it was the number 13 and drew a '13'.

Bruner and Minturn Conclusion

This shows that expectation of what the figure represented was affected by the context that the figure was presented in.

Bruner and Minturn Real world relevance evaluation

Ambiguous figures are used to purposely trick participants, this isn’t a common event in every day life

What Illusion is this and what causes it?

Ponzo Illusion - Misinterpreted depth

What Illusion is this and what causes it?

Muller Lyer - Misinterpreted depth cue

What Illusion is this and what causes it?

Rubin’s vase - Ambiguous figure

What Illusion is this and what causes it?

Ames Room - Misinterpreted depth cue

Sensation

Physical stimulation of the five senses processed by sense receptors

Perception

Brain interpreting and organising the sensory information

Difference between sensation and perception

Sensation is the detection of stimulus, perception is interpreting what it means

Gibsons Direct theory

Perception doesn’t draw on past experience.

Sensation and perception are the same, eyes detect everything we need without having to make inferences.

Gibsons Theory Real world meanig Evaluation

Research was based on 2nd world war pilots, relevant to every day life

Gibsons Direct theory struggles to explain visual illusions

Perception is seen as accurate but illusions trick the brain so theory is incomplete

Gibsons direct theory supports role of nature

Gibson and walk showed few infants who would crawl off the visual cliff, so they’re born with depth perception

Size constancy

Objects perceived as constant size despite size on retina changing with distance

Visual cues and constancies

Information about movement, distance etc

Retinal disparity (Binocular)

Difference between view of one eye and the other

Gilchrist and Nesberg support from similar studies

Sanfords study found similar results which strengthens the validity of the conclusions

Gilchrist and Nesberg ethical issues

Depriving people of food causes discomfort, a case of physical harm

Gilchrist and Nesberg Not like everyday life

Participants judged pictures rather than real food so it may not apply to the real world

relative size

Smaller objects appear further away

Gregory’s theory of perception

Proposes that sensation and perception are not the same. Brain uses incoming information and information which we already know to form a guess