WE tend to assume that we see our surroundings as they really are, and that our perception of reality is accurate. In fact, what we perceive is merely a neural representation of the world, the brain's best guess of its environment, based on a very limited amount of available information. This is perhaps best demonstrated by visual illusions, in which there is a mismatch between our perception of the stimulus and objective reality.
Even when looking at everyday objects, our perceptions can be deceiving. According to the New Look approach, first propounded in the 1940s by the influential cognitive psychologist Jerome Bruner, perception is largely a constructive process influenced by our needs and values. Recent research has provided some evidence for this: in 2006, psychologists Emily Balcetis and David Dunning, then at Cornell University, reported that an ambiguous figure tended to be interpreted according to the self-interest of the perceiver. They now show that the desirability of an object influences its perceived distance.
In the new study, 90 undergraduates were made to sit at a table across from a full bottle of water. Half of the participants were randomly assigned to the "thirsty" condition, and given a serving of pretzels to eat. The rest were placed in the "quenched" condition, and told that they could drink as much of the water as they wanted. Both groups were asked to indicate how long it had been since they last had a drink, how thirsty they were and how appealing the bottle of water was. Finally, they were shown a 1-inch line as a reference, and asked to estimate the distance between their own position and the water bottle.
The participants who had been given pretzels to eat during the experiment reported feeling thirstier than those who drank the water, as would be expected. They also rated the bottle of water as being more desirable, and estimated the distance between themselves and the bottle to be smaller than did the quenched participants. Their state of thirst had influenced their perception of distance, such that the water bottle was perceived to be closer than it actually was.
That the thirsty participants found the bottle of water to be more desirable is not at all surprising - water will quench their thirst, and therefore has immediate physiological benefits. But how about objects that are desirable because of their social value? To investigate this, Balcetis and Dunning asked another set of students to estimate their distance from a $100 bill. One group was told that they could win the money in a simple card game; the other was told that the bill belonged to the experimenter. In this case, the first group find the money more desirable than the first. Again, both groups were asked to estimate their distance from the object in question and again, those who had been told they could win the $100 bill reported it as being closer than those who were told it belonged to the experimenter.
The researchers then asked a third set of participants to complete a survey, and told that it had been designed to assess their sense of humour. Each then watched as their response was graded; half of them were told that their sense of humour was "above average", and the other half were told that theirs was "below average". The surveys were then clipped to a stand, and each participant was asked to estimate how far away it was. Those given positive feedback estimated the stand to be closer than those negative feedback.
A perceptual test which did not require a numerical response was then performed. Participants were asked to throw a small rubber bean bag towards a gift voucher placed on the floor in front of them, and told that the person whose toss landed closest to the voucher would win it. One group was told that the voucher had a value of $25, thus making it desirable to them, while the other was led to believe that it was worthless. This experiment confirmed the earlier ones - those participants who believed the voucher was worth something perceived it to be nearer, and consequently underthrew the bean bag so that it fell short of the target.
The researchers designed one final experiment to rule out the possibility that desirable objects are perceived tobe closer because they evoke a strong emotionalresponse. Participants stood opposite a wall onto which two pieces of tape had been stuck. An object was placed onto a table standing beneath the tape. One group saw a brightly packaged box of chocolates, and the other saw a plastic bag which they were told contained a freshly collected sample of dog faeces. (Both chocolate and faece sevoke strong emotionalresponses.) The participants were then asked to move toward or away from the wall until their distance from it matched that between the two pieces of tape. This time, those shown the chocolate moved further away from the wall than those shown the plastic bag. This seems paradoxical, but is easily explained - the chocolate was perceived to be closer than the faeces because it is the more desirable of the two objects, and so the participants compensate for this by moving further back from it.
These findings demonstrate that higher order psychological states can have a significant effect on visual perception. Specifically, they show that our desires have a direct influence on the perception of distance, such that desirable objects are perceived to be closer than they really are. This mechanism would serve to guide behaviour in the optimum way, by encouraging the perceiver to reach out and acquire the desired object. Further research into this effect is needed, however, as there are other situations in which the opposite could plausibly occur. Undesirable objects which might pose a threat - such as a venomous snake, for example - might also be perceived as being closer than they are so that one can escape quickly.
Related:
- Interpreting hybrid images
- How we feel affects what we see
- Kicking performance affects perception of goal size
Balcetis, E., & Dunning, D. (2009). Wishful Seeing: More Desired Objects Are Seen as Closer Psychological Science. DOI: 10.1177/0956797609356283.
Balcetis, E. & Dunning, D. (2006). See What You Want to See: Motivational Influences on Visual Perception. J. Pers. Soc. Psych. 91: 612-625. [PDF]
Brain & Behavior
Comments (11)
Very interesting. For those of us without access to the original research, can you give a sense of how dramatic the numbers are? Is this a subtle effect that shakes out statistically from large samples, or something dramatic and observable at human scale? Either way it's fascinating and thought-provoking. Thanks for the coverage!
Posted by: Dan | January 9, 2010 3:03 PM