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How close is that glass of water, that gift card, that woman? Your perception of distance depends. How thirsty are you? How much money is the card worth? How attractive is the woman? Some very basic aspects of perception may be strongly biased by our desires.
Emily Balcetis and David Dunning recently published a set of studies in which they investigated how desire biases distance perception (in Psychological Science, this year). In their first study, they placed a glass of water across the table from people, showed them a standard sample of an inch, and asked them how many inches to the water. First, however, they made some people really want the water - they fed them a bunch of pretzels (enough to be about 40% of their daily sodium intake!). They were really thirsty. Other people drank 4 cups of water. The people who ate the pretzels saw the water as closer to them than the people who chugged the water. Although Balcetis and Dunning didn't check, I suspect the water drinkers might have seen the bathroom door as closer. Your perception of how far away a glass of water is depends on how badly you want the water. Desire made the water appear closer.
Balcetis and Dunning constructed other fun methods of demonstrating how desire biases distance perception. In one study, participants played a bean bag toss game. The goal was to throw a bean bag at a Visa gift card on the floor. The person who came closest to the gift card would win the card. Some people were told that the gift card had $100 value, whereas others were told that it had $0 value. When throwing, the people who believed the card was worth $100 typically threw short - they acted as if they perceived the card as closer than it was. In another study, they had people stand a standard distance from a bag containing what they thought were chocolates or dog poop (any study comparing chocolate and dog poop is pretty cool already). Oddly, people stood closer to the dog poop. Since they desired the chocolates and saw the chocolates as closer, they had to move further away to match the standard distance.
In all of these studies, people see the desired objects as closer. I'm having a harder time seeing exactly why this occurs. Perhaps desire makes the object stand out against its background. Perhaps desire sets the body to act and motion makes objects appear closer. Either way, I think it is way cool that desire can bias something as supposedly straightforward as distance perception. As I noted in another post, people regularly misinterpret their current state of arousal (see: Is This Love Or Too Much Caffeine? Misattributions of Arousal Strengthen Relationships).
I imagine this may influence perception in social situations as well. Men frequently misinterpret an attractive woman's behavior. They may conclude she is displaying interest by sitting so close to them. Perhaps this would be a reasonable conclusion if she were sitting close. She may not be sitting particularly close, however. Instead the desired object (in this case an attractive woman) may appear closer than the object of desire actually is.
Cognitive psychologists have generally argued that perception reflects processes guided by environmental stimulation and pre-existing knowledge held by the individual. Balcetis and Dunning have shown that the current motivational state of the individual biases perception as well. Desire makes something appear close.
