Those who believe that the 25-cent peep show is restricted solely to humans, guess again. A January study at Duke University Medical Center revealed that male rhesus macaque monkeys will “pay” to gaze at images of female monkey posteriors. The animals gave up quantities of fruit juice for prolonged views of either female hindquarters or the faces of high-ranking males in their society. Scientists say that this behavior may yield clues to why men ogle and women read People, and could lead to a better grasp of autism in humans.
Four male monkeys were allowed to choose between receiving large juice samples and receiving smaller samples accompanied by digital images. By measuring how much juice the subjects were willing to forgo, scientists could determine the value of each image—highest for female rear ends and lowest for low-ranking male faces.
But that doesn’t mean you can use evolution as an excuse for gawking at girlie picsɓ the monkeys’ reactions aren’t necessarily pornographic, scientists say. Rather, the males may be gauging the reproductive potential of their peers. “We think the males are trying to keep track of each stage in a female’s cycle and her receptivity for mating,” says Michael Platt, the study’s co-author.
The payment for images of dominant males surprised Platt, especially because the monkeys wouldn’t look directly at the pictures for longer than a few seconds. In the animal kingdom, a sustained stare can insinuate a challenge, but Platt sees a human connection too. “It’s tradition in hierarchical societies with a dominant authority—an emperor, for example,” he says. “You lower your eyes in
his presence, but when you get a chance you’re going to peek. You just don’t want to get caught.”
The connection with autism, a condition that affects nearly 1.5 million Americans, is based on understanding primates’ decision-making processes.
People with autism lack the motivation to look at other individuals and don’t pick up on signals such as eye contact, facial expressions and gestures, making normal social interaction difficult.
By studying the monkeys’ brain waves during this experiment, Platt and his colleagues hope to identify neural circuits responsible for socially appropriate interaction. To help autism sufferers integrate more smoothly into social situations, “we might be able to develop treatments that enhance the motivational value of looking at others,” Platt says.
If nothing else, the study might explain humankind’s fascination with high-ranking members of our own society. Why else would we plunk down hard-earned cash for lad mags and macho action thrillers packed full of muscular, good-looking guys, or flock to the newsstands for the latest paparazzi photos of the rich and famous?