Mr. Tamarin Man

Five days a week, Bailey H. Spaulding ’04 treks over to Divinity Avenue, goes to the 10th floor of William James Hall, walks through a door that reads “Authorized Personnel Only” and says hello to the 12 vervet monkeys and 24 cotton-top tamarins that call Professor of Psychology Marc D. Hauser’s primate lab their home.

Spaulding, a biological anthropology concentrator, was fortunate to get into Hauser’s lab research class, Psychology 1152, which is limited to 12 spaces usually reserved for psychology concentrators. She spends her time in the lab testing how well Pinker, Newport, Hrdy and Wrangham—four tamarins named after scientists—can work with tools. She conducts means-means-end experiments to determine whether the tamarins can realize that by using one tool, they can move another tool which will bring them a sugar-coated marshmallow.

“When you work with these animals you really get a sense of what they are capable of doing,” says Laurie R. Santos ’97, one of Hauser’s graduate students, who worked in the lab as an undergraduate as well. Both Santos and Spaulding say that while working with the monkeys is often rewarding, it can also be frustrating. “They all have personalities,” Spaulding says. “You learn that this monkey is really nervous, and that one doesn’t want to come out of her cage and will stretch herself across the cage to grab a raisin without actually coming out.” Of course, care is taken that no monkey is harmed in the raisin-grabbing process. “If it weren’t for the animals we wouldn’t be doing what we are doing,” Santos says. “Their safety and comfort is a huge priority.”

“There is no greater satisfaction then providing a test to animals and watching them succeed or fail, for even the latter tells us something profound about how they see the world,” says Hauser, who started the lab in 1992. During his time at Harvard he has conducted experiments in knowledge perception, acoustic recognition and concept formation, among other fields. He has published four books about primate behavior, taught at several universities in the United States and conducted field research in Uganda and in Puerto Rico, where he invites some of his students each year.

Gustavo M. Gonzalez ’02, a psychology concentrator, wrote his thesis about communication and mate choice among rhesus monkeys based on research he did at Hauser’s field site in Cayo Santiago, an island off the coast of Puerto Rico inhabited by monkeys but not humans. The days in Puerto Rico start at 7 a.m. with a boat ride to Cayo Santiago, after which students research on the island until 3 p.m. and then have free time for the rest of the day.

As an undergraduate, Santos studied tamarins to discover whether or not they know that other individuals have beliefs and desires. She found that they do not, in fact, have “a theory of mind,” which appears to be a uniquely human characteristic. Researchers in Hauser’s lab have studied several problems related to the question of what makes humans uniquely human, including ability to communicate and recognize numbers. Justin A. Junge ’03 assisted Jonathan I. Flombaum ’02, who wrote his thesis on the ability of rhesus monkeys to recognize numbers. “We found that primates can generally differentiate between one, two and three of something, but not between amounts greater than that,” Junge says. Junge and Flombaum, supervised by Hauser, figured this out by presenting the monkeys with varying numbers of grapes and watching as the animals decided which bunch to pursue.

Santos says undergraduates virtually have the same freedom to do research in the lab as grad students do. “Marc takes the undergraduates really seriously,” she says. “You get to act like a grad student when you are an undergrad.”

“The lab couldn’t run without undergrads,” Hauser says. “They not only bring person power, which is needed to run the experiments, but much more importantly, they bring a vitality that is fantastically rewarding to me. So many of the great ideas in our lab have come from the undergraduates. Unlike post-docs and grad students, the undergrads are unjaded, and take critical positions on everything we do. The undergrads are the heart of the lab.”

Students testify that the lab experience, featuring daily coffee hours with Hauser, is a lot of fun, but the best part is still working with the animals. “It’s very humbling to be outsmarted by a one-pound monkey,” Spaulding says. “I think everyone at Harvard could use that once in a while.”