A Study Of the
effectiveness of
Manipulation on
Perceptual Set
©Alex H Parker 2005
1
Contents
Abstract
Introduction
Method
Results
Discussion
References
Appendices
Debriefing
2
Abstract
The aim of this experiment is to see if a perceptual set can influence perception of an
ambiguous picture where the subject is either an old or young woman. A repeated
measures design was used with a sample of 10 randomly selected participants. 80% of the
participants were influenced to see a young woman when a ‘young’ perceptual set was
induced and an old woman when an ‘old’ perceptual set was induced. The results support
the hypothesis that perceptual set influences perception. Some factors related to
resistances to perception of aged persons are discussed.
3
Introduction
A person will experience through their senses information that needs to be interpreted by
the brain. How a person interprets this information depends upon their previous
experience of the stimulus and how it affected them. This package of ideas and
experience is known as a schema. A schema will form a means of recognizing the nature
of a new experience or define what is known as a perceptual set.
Interpretation and selection of information is called perception.
The senses that humans have are touch, smell, hearing, and vision. These senses are
the only resources that a human has for experiencing their environment and these
are the sources of the information that are interpreted to create a perception.
People can have the same sensations in the same environment but interpret the
information they receive through their senses differently.
For example an event where a person raises their voice may be interpreted by one person
as aggression, and as someone trying to be heard in a crowded room by another.
What a person sees and notices is a caused by perceptual set. A mechanic may notice an
old car and see smoke coming out the exhaust, and a young single man might notice a
beautiful woman driving a car.
Both the mechanic and the single man saw the same thing but their perception was
different. This is a demonstration of perceptual set.
According to Allport(1955) a set is ‘a perceptual bias or predisposition or readiness to
perceive particular features of a stimulus.’
This means that a set is a temporary lowering or raising of our threshold for perceiving
something. This includes what we choose to perceive and how we make sense of it.
A set acts as a selector in the way that it only brings to our attention certain things that
we experience by sensation. We are ready to perceive these selected things when it is
most relevant to us. For example we hear our name in a noisy room but all other words
are not noticed, we notice more airplanes when we are about to fly in one, and notice
more cake shops when we are on a diet.
Kelly performed an experiment where two groups of students where given a brief
description of a speaker before being introduced. The descriptions were identical but one
group had the word warm in the description and the other the word cold.
The students were asked to rate the speakers performance after his speech. It was found
that the students given the warm description viewed him as humorous and kinder and
4
they also participated better in the class discussion with the speaker than the group given
the cold description.
The two conditions had given the two groups different perceptual sets. Their interaction
during the lecture also suggested that the two groups had a positive or negative
prejudice toward the speaker based upon their descriptions.
‘Solomon Asch’ termed the words warm and cold as ‘central traits’
‘Luchins 1957’ suggested that What we experience through our senses first has the
greatest effect on impression formation. He demonstrated in ‘the story of Jim’ that if a
person is presented with a friendly or lonely part of a story first that this will have a
strong effect on the perception the listener has about the character ‘Jim’. This is called
‘Primacy Effect.’
The aim of this study is to demonstrate that individuals can manipulate another
person’s perception, by verbally inducing a perceptual set using ‘primacy effect’ and
‘Central traits.’
The experimental hypothesis is that, what people perceive (DV) in an ambiguous
drawing can be controlled and altered by verbally manipulating perceptual set (IV).
The null hypothesis is that there will be no relation between the presented words (IV)
and what is perceived (DV).
5
Method
I used a repeated measures design in this experiment, as it was necessary to use the
same individuals for both conditions to see if perception can be manipulated.
The independent variable is the ‘Central trait’ word and ‘stereotypical words’
presented to the participant. In the first condition, the words were from stereotypes of old
age, in the second from stereotypes of youth.
The dependant variable is the percentage of participants who:
• perceive an old person in an ambiguous picture that could be seen as an old or young
person when their perceptual set is manipulated by ‘old’ words and who also
• see a youth in an ambiguous picture that could be seen as an old or young person
when their perceptual set is manipulated by ‘young’ words.
Participants
Participants were obtained by random sampling. This was done by stopping 10 people at
random in a busy local park (in a non-threatening manner) who were not with a
dependent child or adult. This was to avoid extraneous variables that could interfere
with the effect of the independent variable i.e. already have a strong set based upon
their immediate circumstances. They were all aged over 18 to avoid the need for parental
consent and to minimise any perceived threat. The same participants were used for both
conditions; this was necessary, as their perception in both conditions will demonstrate if
it is possible to manipulate human perception.
The study was ethical because it respected the participants right to refuse to take part and
They were told that the aim of the study clearly. Also the instructions were simple so as
not to cause embarrassment and distress, and a debriefing was given after the experiment
where the ambiguous pictures were explained and the participants were given the
opportunity to ask questions to clarify their understanding of the experiment. The
participants were asked to sign a consent form to show they agreed to participate.
Materials
Two similar 'old woman/young girl ambiguous pictures', which are not recognizably
similar. It was necessary to use 2 versions of the picture to minimise demand
characteristics – that is, the participant guessing what answer is required of them.
A Table to record the results of what was perceived and the success of attempted
manipulation upon perception.
6
Procedure
Participants did the experiment alone with the experimenter and were unlikely to know
each other and explain to other participants what the experiment involved. It was
explained to them that they would be given a description of a person and then be shown
asked to identify the age of that person in a picture. The procedure was then repeated
using the different description and another picture. 5 people were given the ‘old’
description first and 5 were given the ‘young’ description first. This was to
counterbalance for order effects.
‘Condition A’
Old woman description
To produce a primacy effect I started with the central trait word ‘Cold’ followed by
descriptions that are stereotypical of old people (see appendix).
The participants were then presented with the ambiguous old/young picture and asked the
age group of the subject in the picture. Their answer was recorded.
Condition B
Young girl description
The participants were then asked to listen to words describing another person that they
were going to see a picture of and they were presented with a second list of words.
To produce a Primacy effect for the new induced ‘set.’
The new list of words began with the central trait word ‘Warm’ followed by words
stereotypically related to youth.
The participants were then presented with the different design of the young/old picture
and asked the age group of the subject, and their answer was recorded.
Where there is no difference in perception the result is void and manipulation will have
been unsuccessful.
7
Results
The results have been put onto a table of percentages, even though there were not enough
participants to fully justify this kind of presentation. However, this presentation may
misrepresent the importance of this small-scale study and unreasonably generalise the
results to the rest of society. It does however give credibility to further research. The raw
data is in an appendix.
The results demonstrated that it is possible to manipulate perception by introducing a
perceptual set verbally. 8 out of 10 participants perceived an old woman in condition ‘A’,
and were successfully manipulated to perceive a young girl in condition ‘B’. 2 out of 10
participants only saw a young girl and appeared to be unaffected by the stereotypical
words and central traits. However the latter did have difficulty in perceiving anything at
all and took longer to look at the pictures.
Table: Success of introducing a temporary perceptual set and manipulating a new
‘set’ so that something else is perceived.
Percentage of participants
80
20
Successfully manipulated
Not successful
Graph : A pie chart to show proportion of people
influenced by perceptual set to appropriately see an old or
young woman
20
Set induced appropriate
old/young perception
Set did not induce
appropriate old/young
perception
80
The experimental hypothesis has been supported and the null hypothesis rejected.
8
Discussion
The results appeared to support the experimental hypothesis, which asserted that peoples
perceptual set can be induced verbally by another person, and that it can be altered again
verbally so that the participant is in effect manipulated to perceive what the experimenter
wants them to perceive.
Eight out of ten people had a set successfully introduced that led them to see an old
woman and were successfully manipulated to perceive a young girl. Only two out of ten
people had did not respond to the induced set.
The two people who did not respond to the introduced set had difficulty seeing ether the
old woman or the young girl. This could have been as a result of some kind of cognitive
impairment caused by illness, depression, alcohol, medication or other extraneous
variables.
I think that it is likely that the difficulty in perceiving anything at all could be evidence
that the induced set was successful but the participant experienced what Freud called
perceptual defense.
Malcolm Hardy and Steve Heyes State in beginning psychology published by Oxford
University press state:
‘Freud felt that the perceptual process contains systems which protect us from
consciously perceiving information that might cause us cause us extreme upset.’
Eriksen called this theory the ‘The super-discriminating unconscious,’ which blocks
perception if it is likely to be unpleasant. This appears to be an ‘anti perceptual set’ where
the threshold for perceiving something is raised instead of lowered.
I suggest that the words used in condition ‘A’ caused anticipation in the two participants
of something unpleasant and that the ‘Old woman’ was perceived unconsciously by them,
but perceptual defense prevented it from entering consciousness. The fact that the two
participants eventually saw the young girl may have been a result of the amount of time
they continued to study the ambiguous picture. Both participants expressed revulsion at
the image of the old woman when the picture was explained and appeared moderately
upset by it. I suggest the two participants reactions at having the old woman explained
was further evidence of ‘perceptual defense.’ The other eight participants showed no
emotion when they perceived the ‘Old woman.’
I t would be impossible to test a participant before the experiment to see if they are likely
to have a perceptual defense against unpleasant words, this is because any test would
involve inducing anxiety upon the participant and this would be unethical. I believe that
the stereotypical words used should be changed to non-emotional words, as this will
9
reduce the likelihood of distress, although this could reduce the effectiveness of the
manipulation.
In future experiments if I suspected that the participant is having difficulty in perceiving
anything in the ambiguous picture I could assume that perceptual defense is active, and I
would then tactfully end the experiment with that participant. I would also not explain the
picture of the old woman and avoid what Freud called a Carthasis, which means
bringing repressed emotions to consciousness.
It is difficult to know what had the dominant influence on the other eight participants
since the independent variable included stereotypical words, central traits and
primacy effect. In future experiments I believe it would be effective to separate these
three variables into separate experiments of the same nature to see which has the
dominant effect.
However, in this experiment not all participants started with condition ‘A’. This
alternation of which condition is presented first should have reduced Perceptual Defense
affect and may in the majority of cases had an effect upon perception after manipulating
the perceptual set. In a future experiment the stimulus pictures should also be
counterbalanced, since they may have influenced the results here.
The amount of participants used was very low and it would be impossible to generalise
the results to the rest of the population. I believe that doing the study with a small number
of participants was effective in bringing credibility to further study and highlights ethical
issues that may not have been given consideration if more participants were used. In a
future study, many more participants would be used.
The results of the study appear to suggest that people are susceptible to having their
perceptions manipulated by people and organizations. This may be used to incite
prejudice or appreciation to certain minorities’ political movements and commercial
products. This study also seems to suggest that each human’s autonomy is fragile and that
human perception may be a product of externally induced and manipulated perceptual
set.
10
References
Beginning Psychology by Malcolm Hardy and Steve
Heyes, Fifth edition. Published by Oxford University press.
1999. ISBN 0-19-832821-4
Simply Psychology by Michael Eysenck. Published by
Psychology Press1996. ISBN 0-86377-436-9
Psychology & you by David Hargreaves, Kevin Howells &
Elizabeth Ockleford. Published byBPS Books 1997 ISBN
1-85433-226-0
101 key Ideas Psychology by Dave Robinson. Published by
Hodder & Stoughton 2000 ISBN0-340-78155-6
GCSE Psychology by Mike Stanley & John Dickinson
published by National Extension College trust ltd. 2001
ISBN 1-84308-083-4
11
Appendices
Bellow data obtained from the study
Field study table results
Participants
in order
1
2
3
4
5
6
7
8
9
10
Condition One
‘old woman’ description
What is perceived
Old woman
Old woman
Young girl
Old woman
Young girl
Old woman
Old woman
Old woman
Old woman
Old woman
Condition Two
‘Young Girl’ description
What is Perceived
Young girl
Young girl
Young girl
Young girl
Young girl
Young girl
Young girl
Young girl
Young girl
Young girl
Success of
Manipulation
.
Achieved
Achieved
Void
Achieved
Void
Achieved
Achieved
Achieved
Achieved
Achieved
Stereotype word lists with central traits.
Condition ‘A’ word list
Condition ‘B’ word list
Cold (central Trait )
Weak
Sick
Heating
Coronation Street
Bingo
World war two
Memories
Broomstick
Bitterness
Warm (central Trait)
Playful
Joy
Laughing
Pretty
Flowers
Running
Princess
Cute
Flirty
12
Ambiguous pictures used for condition ‘A’ and ‘B’
13
Debriefing
Thank you, for assisting me with this experiment.
The aim of this project has been to study perceptual set and how it can be used to alter
people’s perceptions.
The two pictures that you were shown are called ambiguous. This means that in both
pictures you could see potentially 2 different pictures, either an old woman or a young
girl.
By presenting you with words that related to old people I hoped to condition you to see
the old woman in the picture.
The second set of words that I gave you, were designed to change your perception and
result in you seeing a young girl in the second picture.
I have included another 9 people in this study and will include your contribution be
analyzing the results.
I am happy to answer any questions you have regarding this experiment.
The data that I have collected will be included in my project report for college, but if you
request that your contribution is not included I will be happy to remove your data from
my report. I will also give you a copy of my final report, if you would like to receive one.
14
15