Rumors that Harvard psychology professor Marc D. Hauser was under investigation for scientific misconduct surfaced as early as a year before Hauser took leave from the University, a former collaborator said.

Following news of the investigation first reported by the Boston Globe on Tuesday, scientists have called on Harvard for more information about the probe’s findings.

But the University has kept mum in face of public calls for transparency, and Jeff Neal, spokesperson for the Faculty of Arts and Sciences, has declined to comment on Hauser’s case, stating that “reviews of faculty conduct are considered confidential.”

Hauser is taking a year-long leave of absence after University officials found evidence of scientific misconduct in his laboratory. He recently retracted an article published in 2002 in the journal Cognition that suggested tamarin monkeys learned rules as human infants did after investigators concluded his findings were not supported by the data.

The University’s policy for responding to allegations of misconduct in research lists “the need to protect the rights of the person or persons alleged to have engaged in misconduct” as a consideration in its handling of the case.

The policy also stresses the importance of “protecting the reputations of individuals … to the extent that such protections are appropriate and consistent with other ethical and legal obligations of the Faculty and the University.”

Neal did not respond to a request to clarify the University’s policies Friday night.

But as the University continues to keep the investigation’s findings confidential, academics have begun to question whether Harvard should be withholding information about the nature of the scientific misconduct.

“It’s just kind of terrible for the confidence that the public has in the scientific community,” said a former collaborator who requested anonymity due to the nature of the investigation. “It degrades the credibility of everybody to some extent.”

Per federal requirements, Harvard will report its findings of scientific misconduct to federal agencies that funded the research for a second review, Neal said in an e-mailed statement Thursday. The federal agencies will make its conclusions publicly available upon finding evidence of scientific misconduct, Neal said.

Hauser’s undergraduate research assistants and colleagues have remained tight-lipped about the investigation, expressing loyalty to the scientist who has been a mentor to many.

Of the seven undergraduates previously listed on Hauser’s website before the information was deleted, three declined to comment, and the rest did not respond to interview requests. Only six of Hauser’s 20 collaborators listed on the site responded to interview requests, and all but one declined.

“Marc is a beloved scientist, teacher, and colleague,” Hauser’s friend and colleague, psychology professor Steven A. Pinker wrote in an e-mail Thursday. Pinker has not collaborated with Hauser on any published studies. “He is widely admired not just for his astonishing breadth and creativity in devising ways to investigate deep problems with elegant experiments, but for his warmth, humor, and lack of pretension.”

Hauser did not respond to an interview request, but Pinker said his colleague will continue to head his lab next year while on leave.

Pinker added Hauser will spend next year working on his upcoming book,“Evilicious: Why We Evolved a Taste for Being Bad.”

—Xi Yu contributed to the reporting of this story.

—Staff Writer Elyssa A.L. Spitzer can be reached at spitzer@fas.harvard.edu.