Individual Differences, Purposes and Needs
Whilst there appear to be some subtle cultural differences in some
aspects of visual perception, it is also worth reminding ourselves that
in terms of perception we have far more in common with the rest
of the human species than with the rest of the animal kingdom. However,
in addition to cultural differences, certain individual differences can
affect our visual perception - quite apart from physiological differences
such as impairment of sight. People differ, for instance, in spatial skills
(e.g. 'mental rotation' - competence in mentally rotating 3D shapes so as
to assess them from another angle).
In a well-known experiment by Asch (1955), one
subject was seated in a room with six other people. Unknown to the
subject the other people were confederates of the experimenter.
The experimenter told the group that accuracy of perception was the
focus of the study. The group was then shown two cards (see illustration
below). On one card was a
single vertical line and on the other there were three vertical
lines of markedly different lengths, one of which being the same as the
one on the other card. The group was told that each individual should match
the line on the first card with one of the lines on the other card. There
were eighteen trials with different lengths of lines on the second card.
In each trial the real subject was second from last in being asked for
a response, thus hearing five other people each time offering their own
answers. In the first two trials the confederates all gave the correct
answer but they only did this four times in the following trials - in the
other twelve trials they were all primed to give the same wrong answer.
About a quarter of
the subjects stuck to their own judgement and gave the correct response.
The rest accepted the majority verdict at least some of the time.
This would suggest that conformity may sometimes influence perception.
Some factors related to personality may have an influence on perception.
One such factor is 'tolerance of ambiguity' (a term employed by Else
Frenkel-Brunswik). In 1951, two
psychologists called Block reported an experiment in which subjects were
placed in a dark room where only a point of light was visible. Since they
had nothing else to go by, all of them saw the light sway in various
directions. However, some reported the light as moving in a constant
direction from trial to trial and to a constant number of inches. Such
people have been described as having a low 'tolerance of ambiguity':
they require more stability than most, and quickly tend to manufacture it
in situations of ambiguity. Other people tend to take longer to
establish such a norm: they have a high tolerance of ambiguity.
Another experimenter, Fisher, reported in the same year comparing
people classified as having high or low prejudice. He briefly showed
both groups a picture of a truncated pyramid (see below) and then asked them to
draw it from memory. About 40% of people tended to draw it as
symmetrical, equalizing the two margins of the drawing. This is quite
usual, since memory simplifies. But after a four-week interval, 62%
of the prejudiced group and only 34% of the tolerant group equalized the
margins. One group seemed to need a clear and simple image much more than
the other group did. Those tolerant of ambiguity seemed to favour
uniqueness (for both Block & Block and Fisher see Allport 1958, 377-8).
Differences in cognitive style have implications for perception.
Jerome Kagan outlined a difference in cognitive style which he
referred to as impulsivity vs. reflectivity. When asked to find a match
for a 'familiar figure' (such as a
drawing of a telephone) from a choice of 6, some people seem habitually
'leap in' with a response before checking the alternative fully - these
are the impulsives - whilst others seem unwilling to respond until they
are sure that they have made the correct choice - these are the
reflective types.
Another kind of cognitive style was referred to as 'field dependence or
independence' by Herman Witkin. Field independence refers to an aptitude
for disembedding figures from their contexts. Someone who finds words
easily in word-search grids has considerable field independence. There
is a current vogue for Where's Wally? books in which one has to
find a recurrent character amidst a crowd of people and a frenzy of
depicted activity on a very detailed double-page spread. Those who are
good at this are field independent. Similarly children's puzzles
sometimes include the task of identifying faces, objects or animals
'hidden' in a relatively detailed drawing (an adult equivalent sometimes
uses paintings). These are of course very artificial tasks, but field
independent people would be just as quick at spotting someone in a real
crowd.
Gender plays a part in perception too. One gender-related influence
concerns how our attention may be drawn to different aspects of a scene
or image. In a study by Hess (1965) the eye-movements of a man and a woman
were compared when they looked at a figurative painting by Leon Kroll called
'Morning on the Cape', featuring a bare-backed man ploughing with a horse,
and two women - one in the foreground and another leaning against a tree.
Both subjects began scanning the painting from almost the same point,
but the location, duration and sequence of their gaze were different.
Unsurprisingly, the female observer
paid much more attention to the male figure in the picture than the man
did, and the male observer paid more attention to the female figure in
the foreground than the female observer did. The woman observer focused
only on the head of the foreground woman whilst the man focused on both
the head and the upper body of this female figure. The female observer
did not focus on the house and field at all, whilst the man did. This
direction of attention reflects conventional gender stereotypes of course.
Using ambiguous doodle-like black-and-white figures (see illustration
below), Coren, Porac and Ward
(1978, 413) found gender differences in interpretation. A figure which was
more likely to be viewed as a brush or a centipede by males was more likely
to be viewed as a comb or teeth by females. Another figure viewed as a
target mostly by males was more likely to be viewed by females as a dinner
plate. And a third figure which was viewed mostly by men as a head was
viewed mostly by females as a cup.
Other roles can also influence perception. An aerial
photograph of a river delta may appear obvious to a geographer or a pilot,
but if the image lacked an explicit label, others might have quite
different interpretations. What is Corvus corax to a professional
ornithologist is simply a pest to some farmers, an ill omen to the
superstitious, 'Old Grandfather' to the Koyukon Indians of the subarctic
forest of North America, a crow to most of us, and a raven to the
amateur naturalist.
Prejudice can affect perception as Gordon Allport and Leo Postman showed
in a famous study (1945). After briefly looking at a drawing of figures
inside an underground train - five men, two women and a baby, with two of
the men standing - a black man and a white man face-to-face in
the centre of the picture. Observers were asked to describe what they had
seen. Over half of the observers reported having seen a cut-throat razor
in the hands of the black man. Some even claimed that he had been
'brandishing it widely' or 'threatening' the white man whereas it was
actually in the left hand of the white man standing with him. This
experiment was part of a study of rumour so memory as well as perception
was involved.
Many factors which play a part in influencing how things are perceived
are relatively 'stable' or long-term individual factors. These include
personality, cognitive styles, gender, occupation, age, values,
attitudes, long-term motivations, religious beliefs,
socio-economic status, cultural background, education, habits and
past experience. But there are other factors which may contribute to
individual differences in perception which are more transitory. These
include current mental 'set', mood (affective/emotional state), goals,
intentions, situational motivation and contextual expectancies (Warr
& Knapper 1968).
It is worth reminding ourselves that even photographs reflect not only
the scene they depict but the purposes
of the photographer. As Susan Sontag noted: 'photographs are as much an
interpretation of the world as paintings and drawings are' (Sontag
1979, 7). A photograph is a particular photographer's selection from the
world of something which they regarded as significant for some reason and
is framed in a way which reflects certain considerations. Such purposes
include:
'Nobody takes the same picture of the same thing', so 'photographs
are evidence not only of what's there but of what an individual
sees, not just a record but an evaluation of the world' (Sontag
1979, 88). Furthermore, each photograph alludes to photographic conventions:
Returning to the perception of images, a well-known study by Yarbus
(1967) showed how the eye-movements of observers of pictures varied
according to the questions they were asked to consider. In relation to
a figurative painting showing people in a sitting room and a figure at
the open door, people were asked to estimate the material circumstances
of the family in the picture, to give the ages of the people in the
picture, to suggest what the family had been doing before the arrival of
the 'unexpected visitor', to remember the clothes worn by the people,
to remember the position of the people and objects in the room, and to
estimate how long the visitor had been away from the family. The pattern
of eye movement and the areas on which the gaze rested in each case
were markedly different.
Here is a rough idea of the painting which Yarbus's subjects were
asked to look at...
And here one recorded pattern of eye movements of an observer looking
at the painting. We clearly do not scan pictures in either a random
or robotic manner.
Levine, Chein and Murphy (1942) presented people with a set of ambiguous
line-drawings and asked them to describe what they saw. One group was
hungry whilst the other group had just eaten. The ones who were hungry
more often perceived food items in the ambiguous drawings than those who
had just had a meal. Current needs can thus affect perception.
In a well-known experiment conducted by Jerome Bruner and Cecile Goodman
(1947), two groups of children were asked to judge the size of coins. One
was a poor group from a slum area in Boston and the other was an affluent
group from the same city. The poor group over-estimated the size of
the coins far more than did the affluent group. Thus social values
and individual needs can influence perception.
Dannenmaier and Thumin (1964) asked 46 nursing students to estimate the
heights of the Assistant Director, their instructor and two fellow-students.
The researchers found a relationship between perceived status and
estimated height. Those in authority were judged to be taller than they
actually were, whilst those in lower status were judged to be shorter.
Memory as well as perception may have played a part here. Perceived size
was clearly related to the importance ascribed to the people perceived
in this experiment.
Thematic Apperception Test (TAT) cards are sometimes used in
psychoanalysis as a way of exploring the thoughts and feelings of the
person interpreting the ambiguous but figurative situational images
depicted on the card. The scenes depicted are emotionally charged but
open to interpretation in a variety of ways. The use of such images
acknowledges the role of personal concerns in perception.
Mood may also influence perception. Leuba and Lucas (1945) conducted
an experiment involving the description of 6 pictures by 3 people when in
each of 3 different moods. Each mood was induced by hypnosis and then the
pictures were shown. Here are the descriptions that one person gave for a
picture of 'four college men on a sunny lawn, listening to radio':
We need to remind ourselves that it was the same picture each time. Mood
can clearly play an important part in perception.
Albert Hastorf and Hadley Cantril (1954) conducted what became a famous
study of the reactions of opposing fans to an American football game
between two university teams - the Princeton Tigers and the Dartmouth
Indians (Princeton won). It was a rough and tense game. One Dartmouth
player was taken off with a broken leg and a star Princeton player
suffered a broken nose. Both sides were penalized. Undergraduate students
from each of the universities were asked for their reactions to the game
a week later.
69% of the Princeton students who had seen the game saw it as 'rough and
dirty' compared to only 24% of the Dartmouth supporters, whilst 25% of the
Dartmouth students invented their own category of 'rough and fair'. When
shown a film of the game later, the Princeton students 'saw' the Dartmouth
team make over twice as many rule infractions as were seen by Dartmouth
students. Hastorf and Cantril comment that:
For these students, the perception and recall of what might seem to be
'the same event' involved a very active construction of differing
realities. Hastorf and Cantril's classic case-study emphasizes the crucial
role of values in shaping perception.
The data here indicate that there is no such 'thing' as a 'game' existing
'out there' in its own right which people merely 'observe'. The game
'exists' for a person and is experienced by him only insofar as certain
happenings have significances in terms of his purpose.
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