A Dutch social psychologist issued a public apology Wednesday after an inquiry found he faked or manipulated data in at least 55 publications.
Diederik Stapel said in a statement aired on the national broadcaster NOS he had "failed as a scientist" for perpetrating one of the worst cases of scientific fraud on record in the Netherlands.
But commissions set up to investigate his fraud at three universities, which first came to light last year, concluded it was not only Stapel who failed, but also the academic research community culture which allowed "this large-scale fraud ... to go unnoticed for so long."
"In the case of the fraud committed by Mr. Stapel, the critical function of science has failed on all levels," the commissions' final report said. "Fundamental principles of scientific method were ignored, or set aside as irrelevant."
Pim Levelt, who led the inquiry into Stapel's work at Tilburg University, said an analysis of Stapel's work showed "research practices in which sloppy science was the order of the day."
Stapel was fired last year by Tilburg university after his fraud was first revealed.
Prior to his unmasking as a fraud, Stapel had been a darling of the Dutch social psychology community, known for headline-grabbing research.
He once claimed to have shown that the very act of thinking about eating meat makes people behave more selfishly and he co-authored a paper published in Science magazine that said white people are more prone to discriminate against black people when they encounter them in a messy environment, such as one containing litter, abandoned bicycles and broken sidewalks.
"These findings considerably advance our knowledge of the impact of the physical environment on stereotyping and discrimination and have clear policy implications," the paper's abstract said.
Science later retracted the paper, according to the magazine's website.
Stapel's fraud was eventually uncovered when three graduate students became suspicious of data he supplied them without allowing them to participate in the actual research. When they ran statistical tests on it themselves they found it too perfect to be true and went to Tilburg University's dean with their suspicions.
Levelt said Wednesday that if experiments did not produce the results Stapel wanted, he would repeat them with minor changes. "Only the results that did meet expectations were reported. That way, a hypothesis is, of course, always confirmed."
The commissions confirmed fraud in 55 publications during Stapel's time at Tilburg and Groningen universities and found "indications" of fraud in 11 other papers from his work at the universities of Groningen and Amsterdam.
Levelt said Stapel's work had severely shaken academic research circles.
"The foundation of scientific cooperation is mutual trust," Levelt told reporters in Amsterdam. "When that trust is badly damaged as it was in the Stapel case it erodes the foundation of scientific research."
Stapel said he felt "deep, deep regret for what I have inflicted on others.
"I feel sadness, shame and self-reproach," he added. "The truth would have been better off without me."