University President Lawrence H. Summers wandered off his terra firma of economics and into the tricky realm of behavioral genetics last Friday when he speculated that innate ability might account for the underrepresentation of females in the natural sciences.

In the days after Summers’ remarks made national headlines, several Harvard psychologists have weighed in on their validity, with some rallying to Summers’ defense and others lamenting his lack of tact.

Pierce Professor of Psychology Ken Nakayama wrote in an e-mail Tuesday that Summers’ comments “undermine our faculty’s otherwise diligent efforts in the recruitment and retention of outstanding female scientists.”

Summers responded Tuesday night that attracting more women to Harvard’s science faculty remains a top priority. “[N]othing I said bears on the way any individuals should be viewed,” he told The Crimson.

But Hobbs Professor in Cognition and Education Howard E. Gardner ’65 suggested that Summers—in keeping with his high-profile post—should have phrased his remarks more sensitively. “President Summers was absolutely within the pale of normal academic discourse,” Gardner wrote in an e-mail. But, Gardner added, “if he wanted to make these remarks publicly, it would pay him to run them by some colleagues—including people like me—to reduce the chance that he would be misunderstood.”

While Summers spoke extemporaneously from a set of notes, “I would have advised him to have spoken from a written text,” Gardner said.

Gardner said that “Summers is correct that men are overrepresented at both ends of the bell curve in terms of math-science-spatial capabilities, just as they are overrepresented at both ends in terms of many conditions, both positive and pathological.”

But Gardner said that “overrepresentation is not necessarily due to genetic factors.” He noted that Asians tend to outperform non-Asians on several tests that predict scientific aptitude—a phenomenon that likely reflects societal influences rather than biological differences.

Summers’ remarks last Friday touched upon the age-old “nature-versus-nurture” debate—a question that psychologists have increasingly dismissed as excessively simplistic.

“It rarely makes sense to talk about genetic versus environmental influences,” wrote Professor of Psychology Daniel T. Gilbert in an e-mail. “The ‘nature versus nurture’ debate is over. Nobody won and the game was called on account of pointlessness.”

INNATE INFLUENCE

Lindsley Professor of Psychology Stephen M. Kosslyn explained in an e-mail yesterday that “there are two types offactors that could allow innate characteristics to explain whether a person (male or female) chooses a career in science, namely ‘indirect’ and ‘direct.’”

“Science is combative,” Kosslyn wrote. “People argue aggressively and get into intense disputes.”

If biological factors determine comfort level in combative situations, then gender differences could partially explain the underrepresentation of females in elite academic science, Kosslyn said. But he noted that “one’s comfort level in combative situations might have nothing to do with innate factors...but instead might reflect socialization.”

As for “direct” influences on academic achievement, Kosslyn said that “solid evidence” supports the hypothesis that men may have stronger spatial abilities while females may have stronger verbal abilities. Even so, Kosslyn said, “some women will be better than some men at spatial abilities, and some men will be better than some women at verbal abilities.”

Kosslyn said that there is insufficient evidence to support the conclusion that differences in innate abilities account for female underrepresentation in the sciences. But, Kosslyn stressed, Summers only “suggested that this is one hypothesis that should be considered. By definition, a hypothesis remains to be tested.”

Kosslyn said that separating indirect from direct factors is a key first step toward increasing the number of female scientists. “For example, if indirect innate factors affecting temperament are at work, it might be easiest to change the relevant aspects of the culture of science,” Kosslyn said.

WALKING OUT

Several scholars questioned the decision of MIT biologist Nancy Hopkins ’64 to walk out of Summers’ talk at the National Bureau for Economic Research last week—although Hopkins insists that she only left because Summers’ remarks were so repugnant that she became physically ill.

“[S]cience entails listening to opposing points of view and then refuting them with arguments and evidence,” Gilbert wrote. “Any scientist who has to leave the room when their point-of-view is challenged is really in the wrong business.”

“[T]he saddest thing about this incident is that it puts a chill on the open exchange of ideas about a solution,” Gilbert said.

Others questioned Hopkins’ decision to go the press with her concerns.

“[Summers] was specifically asked to be ‘provocative,’ and the meeting was defined as a private event at which participants could speak their mind freely without worry of being quoted...in the press,” Kosslyn wrote. “Given those ground rules, President Summers was absolutely being appropriate.”

—Staff writer Daniel J. Hemel can be reached at hemel@fas.harvard.edu.