Without realizing it, people will perceive things according to how they want to see them, a new study suggests.

"There is an age old hypothesis in psychology that a person's wishes, hopes and desires can influence what they see," said David Dunning, Cornell University psychologist and co-author of the study. "This theory had lay dormant for about 40 years, though, without any supporting evidence. We wanted to test the murky waters again."

In five separate tests conducted by Dunning and a graduate student, Emily Balcetis, 412 volunteers from Cornell were presented with an ambiguous picture that could be interpreted as two distinct figures?either a horse's head or the body of a seal, for example. They were told they would be assigned to a taste test of either fresh-squeezed orange juice or a gelatinous, clumpy and rather unappealing veggie smoothie, depending on whether they saw a farm animal or sea creature.

More often than not the participants chose the figure that would lead them to the juice.

The trick to making the study meaningful was making sure the test subjects didn't know what was going on, Dunning said, noting that the generally high IQ of Cornell students made cheating a real possibility.

"The figures we used were chosen so we knew the people weren't just lying or tricking us," Dunning told LiveScience. "We also tracked automatic, unconscious eye movements which were out of their control."

Not only did participants routinely see the figure that produced favorable results, their eye motions indicated that they were never aware of the alternate option being available.

Other scientists who have studied the connection between belief and physiological reactions in the eye, now supported by Dunning's research, point to its possibilities in the world of positive thinking and self-motivation.

"Determining whether a person walking towards you is smiling or smirking, how close the finish line seems in a race or how loud a partner?a wife, husband, lover?is yelling during an argument," Dunning gave as examples that could arise in life. "Could we interpret ambiguous situations towards our expectations and hopes and away from our fears? That is the ultimate question."

The study will be published later this year in the Journal of Personality and Social Psychology.