Psychology - Perception

  • Created by: EmilyT432
  • Created on: 19-03-17 12:39

Key Concepts

Sensation = The physical process of collecting data from the environment via the senses (e.g. a series of lines + shapes).
Perception = The cognitive process of interpreting data once it has been sensed (e.g. interpreting a series of lines + shapes as a chair).

Illusion = the effect of misinterpreting data.
Geometric illusions = when one line or another is somehow distorted and we make an error in our perception. (e.g. ponzo illusion)
Ambiguous figures = a picture of a drawing that can be seen in more than one way. (e.g. necker cube)
Fictions = seeing something which is not actually there. (e.g. kaniza triangle)

Visual constancies = allows us to see things as remaining the same even though the physical characteristics are constantly changing.
Shape constancy = the ability to perceive the shape of an object as constant even if it appears to change through movement (e.g. the door)
Colour constancy = the ability to perceive the colour of an object as constant even as it appears to change through lighting (e.g. grass at night)

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Depth Perception Cues

Depth Perception = refers to the ability of our eyes and brain to add a thrid dimension (depth) to everything we see.


  • Linear perspective = as you look down a road/path, the lines converge (come together) as the get further away. This helps us to interpret the distance.
  • Height in the plane = if an object is higher in an image, it usually means that it is further away.
  • Relative size = when we know that two objects are actually the same size, but one looks smaller, we recognise the smaller one as further away.
  • Superimposition = if one object is blocking/ hiding part of another object, we know that the object we can see the whole of must be closer.
  • Texture gradient = as things get further away, you can see less detail about them.
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Types of Processing

Top-down processing:
Our brain determines what we perceive. This means that past experience including our culture, expectations and motivations can influence what we interpret. This means we might interpret the world differently to others.


Bottom-up processing:
Perception occurs immediately based on exactly what the eyes sense, rather than what the brain has interpreted it as. This is a fast, data driven process based on instinct rather than the past. This means we all see the world the same way.


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Core Theory - Constructivist Theory

Supports the idea of top-down processing.
According to this theory we have perceptual sets. Perceptual sets mean that we have a tendency to perceive a scene, situation or object on the basis of what you expect to see.
The way we perceive the world as based on expectations (what has already happened influences what you expect to see next), if you are expecting to see someone you are more likely to see them in a crowd.
The way we perceive the world is influenced by motivation. For example, if we are annoyed or tired, we are more likely to perceive a repetitive noise as irritating.

1. The theory believes that our past experiences influence our perception and yet a sixth month old will not crawl across an imaginary cliff, despite their limited experience of the environment. According to the theory, young children shouldn’t understand that there is a cliff drop.
2. If the theory is correct, we should not fall for the same illusion multiple times. If perception is about the experience then we should learn not to be fooled by the illusion a second-time round.
3. All individuals naturally develop perception skills without being taught them This suggests that it is an instinct rather than something based on experience.

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Alternative theory - Nativist Theory

Perception is a result if a bottom-up process.
The theory believes in instinct and biology and so perception is a natural, instinctive process.
According to the nativist theory the brain does not have an impact on what we see, it just analyses and interprets what we sense.
The process is as natural as something like breathing, which is why we perceive things so uickly.
As it is a natural biological process, all humans tend to see the world the same way. We have all evolved in the same way and so we perceive our world identically.

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Haber and Levin - Core Study (Describe)

Aim: To test which processing approach explained perception more accurately.
Sample: 9 male college students from the USA, who had been tested for good eyesight.
Haber and Levin used a repeated measure design
Method: The students were driven out to a large grassy field, surrounded on three sides by trees. The field had been divided into four separate sections.

  • real world objects which have a known size
  • real world objects which could vary in size
  • cardboard cut outs of three geometric figures
  • empty section

The students were taken to the centre of the field and asked to face one of the sections in groups of three. They then recorded their estimates about how far away the objects were, this was repeated until they had estimated the distance of all 45 objects.
Results: The participant’s estimates of distance were the most accurate for the real-world objects which were a standard size. however, their estimates for the other objects were not so accurate. they concluded it is easier to estimate the distance of familiar objects because the participants were relying on their past experiences, with the other objects, they couldn’t use their prior knowledge in the same way. they couldn’t be sure of their size and so couldn’t be sure of their distance.
Conclusion: This suggests that the constructivist theory is more reliable than the nativist theory.

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Haber and Levin - Core Study (Evaluate)

1. The study only used 9 participants. These participants were all male (gender bias) college students (age bias). The study also only took place in USA (culture bias).

2. The study lacked ecological validity as it was not a real-life situation and so we cannot generalise it. The task was also unfamiliar and occurred in a fake scenario.

3. Even though Haber and Levin classed them as objects of a 'known size' it doesn’t mean that the participants would have known the size. They may have viewed that as a different size. The categories may not have been accurate representations of the objects.

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Applications of Research - Subliminal Advertising

Subliminal = existing or operating below the threshold of consciousness (meaning you don’t realise you’ve sensed them).

Subliminal advertising = a brief sound or image message that is directed at us without us being aware of it, with less that 50% chance of us spotting it.

In the late 1950s, filmgoers were reported as having bought 50% more popcorn and 18% more coca cola when the words 'Eat Popcorn' and 'Drink Coca-Cola' were projected on the screen subliminally for 1/3,000th of a second.

This was considered unreliable as the film being shown was 'Picnic' and contained several scenes of eating and drinking, perhaps the film itself and not the hidden messages caused this increase in sales?

In a superstore, research was done into background music being played and it noted the effect the music had on customers shopping habits. French music caused a substantial increase in sales of French wine.

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Applications of Research - Advertising for the Bra

Research has shown that different parts of the brain are responsible for processing different types of information. Research has also shown that information entering through the left eye goes to the right side of the brain and vice versa.

Psychologists recommend that the emotional part of a TV advert should be on the left side of the screen so that it can be interpreted by the right side of the brain. Any messages of words should be on the right side, to be interpreted by the left side of the brain which deals with language.


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Applications of Research - Context in Advertising

Perception of an object can be affected by the context it is presented in.

  • Some Jeans look sexier when modelled by a young woman/man than when they are modelled by an older woman/man.
  • The same meat pie may look bigger and more appealing on a small plate with a few vegetables than on a huge plate with potatoes.
  • The same car may appeal to a female audience more when it is driven by a woman as opposed to a man.
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