Monkeys Are Willing To 'Pay' for a Glimpse Of High-Status Apes Animals Surrender Perks To Peek at Photographs Of Dominant Simians By MARILYN CHASE Staff Reporter of THE WALL STREET JOURNAL February 11, 2005; Page B3 Monkeys will pay for a glimpse of power and beauty, scientists have found, much as people pay for magazines offering a peek at Donald Trump's wedding or Jennifer Lopez's Oscar gown. In a study titled "Monkeys Pay Per View," neuroscientists at Duke University discovered that rhesus monkeys will give up a portion of hard-earned perks for a peek at pictures of the dominant leaders and nubile females in their troop. But they won't pony up to look at faces of subordinate simians. Instead of money, the simian unit of currency is cherry juice, a treat that scientists use to reward laboratory monkeys for doing tasks. Monkeys assigned the photos a precise value in swigs of the sweet fluid. Published in the journal Current Biology, the study, by assistant neurobiology professor Michael Platt and postdoctoral research associate Robert Deaner, is part of a line of research into how the brain assigns value and makes decisions based on the cost and benefit of an action. The field, known as neuroeconomics, has fascinated biologists for a decade. Supported by the National Institute of Mental Health and the Cure Autism Now Foundation, the study could advance understanding of autism, a developmental disorder marked by inability to look at others' faces, interpret their social significance or manage human interactions. In the jungle, such skills spell survival: Monitoring faces of powerful individuals who could beat you up or steal your food is a key to staying alive. Surveying readiness of potential mates is crucial to a successful reproductive strategy. "You've got to know who's who, who's got the power, who might be a potential ally, potential foe or potential mate," Dr. Deaner said. During the experiment, four monkeys named Wolfgang, Sherry, Dart and Niko were seated in chairs facing a computer monitor, as researchers electronically monitored their gazes. The monkeys watched a slide show featuring pairs of photos taken of their 12-member troop. Viewing a particular image triggered a squirt of juice. The monkeys' gazes showed a clear preference for power and beauty, no matter the cost. They chose to look at pictures of alpha monkeys of both sexes, and potential female mates, although they had to sacrifice -- or pay more for the view -- by accepting 10% less juice. The photos were of faces of male and female alphas, and, in keeping with how monkeys judge a potential mate's receptivity, the backsides of females. When researchers displayed photos of subordinate or low-ranking monkeys, the study monkeys wouldn't pay or even accept a standard juice ration. Instead, they required a 5% juice bonus -- call it incentive pay -- before they would deign to look. "It was a bit of a surprise," Dr. Platt admitted. "It was almost not worth the extra juice for them to look at low-ranking monkeys. It was actually worse than looking at a gray square," he said, referring to a sort of test pattern that preceded the slide show on the computer monitor. All this resembles the way that people's gaze follows those of high rank at parties or meetings, Dr. Deaner explained. "If one person has power and control, people will monitor them, whereas if people have no say in the meeting, people won't bother looking at them." One interesting finding: Study monkeys would pay just as much juice to look at the faces of the high-ranked females as males, with no apparent gender discrimination. But while monkeys would gaze as long as they could at female hindquarters, they quickly assessed mug shots of male and female power figures and then averted their gaze. In the wild, staring is a challenge that invites an aggressive response. The researchers plan future human studies using functional magnetic resonance imaging to measure how people value visual input, and map the flow of such information to specific brain sites. Paul Glimcher, associate professor of neural science and psychology at New York University, who mentored Dr. Platt while he was doing postdoctoral research at NYU, says monkey pay-per-view has taken the starch out of staid scientific meetings. "It's hilarious," he said. "When they take this study and present it at conferences, people fall over laughing." But the work is important, Dr. Glimcher said, because it offers a common conceptual framework for decision-making by humans and other primates. The research has "taken the issue of your wanting to be -- or be with -- an important monkey, and shown it seems to obey the same rules about monkeys working for juice or humans working for money." All primates living in complex societies have evolved this drive to study what's around them, Dr. Glimcher explained. "People are willing to pay money to look at pictures of high-ranking human primates. When you fork out $3" for a celebrity gossip magazine, "you're doing exactly what the monkeys are doing. "The difference between Michael's study and People magazine," he said, "is that the monkeys actually know the individuals in the picture." Link
