An investigation at Harvard University last year found prominent cognitive scientist Marc Hauser guilty of research misconduct and raised questions about several publications, including a 2007 Science paper on the ability of non-human primates to understand the intentions of a human experimenter by interpreting his gestures. Today Science has published a partial replication of that study that appears to confirm the original findings.
The 2007 study found that chimpanzees, cotton-top tamarins, and rhesus macaques can distinguish intentional gestures, such as pointing to indicate a container with food inside, from seemingly accidental actions such as a hand flopping against a container. Although some researchers raised questions about the study's methods at the time, the findings suggested that the ability to recognize and interpret rational, goal-directed actions—which some researchers thought likely to be a uniquely human trait—have much deeper evolutionary roots.
Following the Harvard misconduct investigation, first author Justin Wood, now an assistant professor at the University of Southern California in Los Angeles, wrote to Science in June 2010 to notify the journal that the investigation had revealed that the original field notes for the rhesus experiments could not be found:
An internal examination at Harvard University determined that there are no field notes, records of aborted trials, or subject identifying information associated with the rhesus monkey experiments; however, the research notes and videotapes for the tamarin and chimpanzee experiments were accounted for. Professor Hauser states that "most of the rhesus monkey observations were hand written by [co-author David D.] Glynn on a piece of paper, and then the daily results tallied and reported to Wood over email or by phone" and then the raw data were discarded. The research assistant who performed the experiments (Glynn) confirmed that these field notes were discarded.
Glynn could not immediately be reached for comment. A profile on the networking site LinkedIn lists him as a research associate at the Nielsen Company, the marketing and research firm known for rating the popularity of television shows.
As a result of the missing field notes, Wood wrote in his letter, the researchers could not verify that individual monkeys were tested in a single experimental condition as intended. The letter says Wood and Hauser returned to Cayo Santiago island in Puerto Rico to redo the experiment with the same population of free-ranging rhesus monkeys. Their findings, including field notes and video trials, are available online and they essentially match those reported in the original paper.
Wood did not respond to a request for clarification of what went wrong with the original experiment, writing by e-mail: "As noted in the study, we replicated the originally reported results. At this time I will let the findings speak for themselves."
A statement issued by Science today says in part:
We stress that this new publication aims only to determine whether the original rhesus monkey experiments from the 2007 paper can be replicated. It has no bearing on questions raised about Dr. Hauser's larger body of work.
Ginger Pinholster, a spokeswoman for AAAS, which publishes Science, says the replication materials were sent out for peer review. Citing the journal's confidentiality policy for peer review, she declined to say how many reviewers reviewed the replication, whether they were the same as the reviewers of the original paper, or whether they received any special instructions. However, she said, "as you might imagine, there was a strong desire to be as thorough as possible in reviewing the replicated findings in this case."
"The results of this replication are straightforward and entirely consistent with those of the original study," says Dario Maestripieri, a behavioral biologist at the University of Chicago in Illinois. "If the authors' interpretation of their results is correct, these findings are very important and represent one of the clearest demonstrations that nonhuman primates can interpret the behavior of other individuals as intentional or non-intentional." However, Maestripieri says there's another possible explanation for the findings: the Clever Hans effect, in which a human experimenter inadvertently provides clues that guide an animal's behavior. "Since the experimenter who tested the rhesus monkeys in the replication study appeared from the video to be the first author on the paper, Justin Wood, he was clearly knowledgeable of the hypotheses being tested and had some strong expectations and desires about the monkeys' performance on the test."
Meanwhile, many questions about Marc Hauser's conduct are still unanswered and will probably remain that way until investigators at the federal agencies that funded his research complete their work. Only they know when that will be, and they are not talking. The Boston Globe reported last week (and Harvard confirms) that Hauser, who has been on leave this year, will not be allowed to teach during the 2011-12 academic year.
His status in terms of research remains unclear, but in a letter to Harvard faculty members last year, Michael Smith, the dean of the Faculty of Arts and Sciences, wrote that "options in findings of scientific misconduct include involuntary leave, the imposition of additional oversight on a faculty member's research lab, and appropriately severe restrictions on a faculty member's ability to apply for research grants, to admit graduate students, and to supervise undergraduate research."