Visual Perception – Perceptual Set

Look closely at the illustration of a seal act for a circus in the figure below. What do

you see?

Would you have seen it differently without the cue?O You may have identified a seal

balancing a ball on its nose with its trainer on the right holding a fish in one hand and a stick in the other.

O However, if you had been told that this picture was of a costume party, how would you then have described it? Would your perception of the same illustration have been different?

What influences Visual Perception?

O Many factors influence visual perception. Generally, these can be categorised into two groups called physiological and psychological factors.

O Physiological factors involve the ways in which our eyes, nervous system and brain process visual information.

O Psychological factors involve mental processes such as our past experiences, socio-cultural background, memory, thinking, language, motivations, emotions and so on

Perceptual SetO Perceptual set is the predisposition,

or ‘readiness’, to perceive something in accordance with what we expect it to be.

O Our expectations of what an object or event will be make us more likely to interpret the object or event in the predetermined way. Perceptual set is often referred to as expectancy

Try to think of examples when Perceptual Set could be good and bad?

O Visual perception can be assisted by perceptual set when we correctly anticipate what something is and therefore interpret it more quickly.

O Sometimes, however, perceptual set can lead to mistakes in perception. Our expectations of what something might be may cause us to notice only the information that is consistent with our expectations and ignore or overlook information that may be relevant

What can effect perceptual set?

O There are several factors that can influence or bring about perceptual set. Most of these involve personal characteristics of the perceiver, such as their motivation, emotional state, past experience and cultural background. Other factors that affect perceptual set involve what is being perceived or the conditions under which it is being perceived, such as the context.

Turn to Page 1.26O Complete the famous actress activity

(2 mins)O INTERESTING – Read Box 3.8 as a

class

ContextO In visual perception, context refers to

the setting or environment in which a perception is made. When organising and interpreting visual information, we take account of the setting and pay more attention to those aspects of the setting that are immediately relevant.

O In this way, context has a ‘focusing’ role in visual perception and usually assists us to make a quick and accurate interpretation of what we are looking at.

Context – how would you perceive this in different places?

For example, consider the different interpretations that could be made of a fast-moving bright light in the sky that has a tail streaking behind it. How would you interpret this visual stimulus if you observed it in the sky over:• outback central Australia?• a war zone?• Cape Canaveral, Florida?• Melbourne's Yarra River on

New Year's Eve• a ship at sea?

Seeing people out of contextO Context can also lead us to make slower or

inaccurate interpretations. For example, have you ever bumped into someone who seems familiar but found you can't recall their name or where you know them from? The person may have been one of your primary school teachers, but because they were ‘out of context’ (that is, in a different situation from that in which you have known them) you were unable to readily identify them

Quickly to the Bruner and Minturn Experiment as a class

O Split the class in two

What happened in the real experiment?

O The importance of context in visual perception was first demonstrated in an experiment by American cognitive psychologists Jerome Bruner and Leigh Minturn (1955).

O In this experiment, one group of participants who were assigned the role of observers (Group A) was shown a visual stimulus for 80 thousandths of a second using a tachistoscope after viewing the series of letters L, M, Y, A. Another group of observers (Group B) was shown the same visual stimulus for the same exposure time after viewing the series of numbers 16, 17, 10, 12.

O The task given to each group of observers was to identify what they saw and to draw it. Results from Group A (who saw the letters first) indicated that 92% of the participants perceived the visual stimulus as a ‘B’. For Group B (who saw the numbers first), 83% of the participants perceived the visual stimulus as a ‘13’

Outcome of the Experiment

O Bruner and Minturn concluded that the context of either letters or numbers ‘set’, or predisposed the observers to interpret the ambiguous symbol in accordance with the type of symbols that had preceded it. A perceptual set, or expectancy, had been established by the time the ambiguous figure was shown. Observers expected the next symbol to be one that was consistent with the established context.

ExperimentsO If we have time to LA 3.23O Ask a student from another class to

come in (or a group of students can do this next lesson)

MotivationO Motivation can also influence

perceptual set. Motivation refers to processes within us which activate behaviour that is directed towards achieving a particular goal. Motives can be influenced by psychological factors (such as interests, ambitions and desires) or physiological factors (such as bodily responses associated with hunger or thirst).

Visual perception can be influenced by our motives

O For example, we see what we want to see, rather than what is actually there. When supporters of opposing teams are sitting side by side at a football match, the difference in their perceptions of the same event may be considerable.

Class DiscussionO Think of some examples when

motivation might effect your perceptual set

Emotional StateO Our emotional state — how we are feeling — can

also influence the way in which we perceive visual information. Different emotions can ‘set’ us to perceive information in a particular way which is consistent with the emotion being experienced.

O For example, a child who is afraid of being in their darkened bedroom may interpret the shadow of their dressing gown hanging on the back of the bedroom door as a ghost, or the teddy bear sitting on the end of the bed as a monster.

O As a class think of some examples

Past ExperienceO Past experience refers to our personal

experiences throughout our lives. This includes everything we learn through experience, both intentionally and unintentionally. Our unique combination of past experiences can lead to many individual differences in perception. Such experiences also predispose, or ‘set’ us to perceive information in a particular way.

O AS A CLASS THINK OF SOME EXAMPLES

Cultural O Culture refers to the way of life of a particular

community or group that sets it apart from other communities and groups. Culture includes such things as the customs, traditions, beliefs, values, attitudes, rules about what is right and wrong, music and food, as well as any other features of that community or group which distinguish it from other communities, or groups.

O Experience with or in a particular culture can influence the way we process and interpret visual information.

Example the Malawi People from Tanzania

O Before the Malawi people had access to photographs, a group of them were shown a black and white photograph of a dog. Despite the fact that many of the observers owned dogs or had experience with dogs, they were unable to identify the subject of the photograph as a dog. Even when the various features of the dog such as the head, ears and tail were pointed out to them, many of the Malawi people still had difficulty interpreting the photograph as a dog and, in some cases, the specific features of the dog, such as the paws and tail (Deregowski, 1980).

O As a class think of some otherexamples

Complete Experiment LA 3.27 as a class

O Page 131

Complete now or for Homework LA 3.25 page 130

O Friday – Visual IllusionO Monday – Visual Perception TestO Wednesday (next week) – Excursion to

Melbourne Museum (bring forms back on Friday PLEASE)

O If you have time on Anzac Day complete: O True/False Page 141O Multiple Choice 142-143O Short answer 144

ReferencesO Most of the definitions and examples

were taken from your Psychology text book.

O J Grivas. L Carter, ‘Psychology for the VCE Student Units 1 and 2’ 5th Edition, 2010, Queensland