Social psychologist Diederik Stapel made a name for himself by pushing his field into new territory. His research papers appeared to demonstrate that exposure to litter and graffiti makes people more likely to commit small crimes and that being in a messy environment encourages people to buy into racial stereotypes, among other things.
But these and other unusual findings are likely to be invalidated. An interim report released last week from an investigative committee at his university in the Netherlands concluded that Stapel blatantly faked data for dozens of papers over several years.
Stapel was removed from his position at Tilburg University in September after three junior researchers raised concerns about his work, suspecting that certain data were forged.
Psycholinguist Willem Levelt, chairman of a committee set up to investigate Stapel's work at Tilburg, the University of Amsterdam and the University of Groningen, described his initial reaction to the charges as "disbelief."
"I have never seen a case where a leading Dutch scientist who was also dean of his faculty was involved with data fabrication," Levelt said in an interview. "But then when we started working on this case, I kept being surprised — because the fraud turned out to get larger and larger."
More than 150 papers are being investigated. Though the studies found to contain clearly falsified data have not yet been publicly identified, the journal Science last week published an "editorial expression of concern" regarding Stapel's paper on stereotyping. Of 21 doctoral theses he supervised, 14 were reportedly compromised. The committee recommends a criminal investigation in connection with "the serious harm inflicted on the reputation and career opportunities of young scientists entrusted to Mr. Stapel," according to the report.
Stapel said in a written statement Monday that he had "failed as a scientist."
Writing in Dutch, he said he had been under great pressure to produce successively better work and he "just wanted to make something more beautiful than it is," according to a translation of the statement. "I have used improper means to [make] the results attractive."
It is rare that a distinguished researcher is able to fake data for so long. But the motivations to do so — power, prestige, pressure to publish — are more pervasive in the scientific community than it might seem.
The interim report describes a man who went to great lengths to maintain the deception. It alleges that Stapel would design detailed experimental procedures, and — unusual for a professor — would handle the data collection himself rather than pass it off to a graduate student.
He would have partners in the work, usually students or other researchers, help him collect study materials — such as questionnaires and sweets for participating children — and pack them in his trunk, ostensibly to be driven to a school where he had arranged to perform an experiment. Stapel would then produce a collection of data, supposedly processed by some unknown assistant.
These convenient tables of data would be handed off to the unwitting study partners for analysis. The original data was never collected, according to the report.
Scientists from various fields have been scandalized by elaborate and long-lasting frauds, said Gerben van Kleef, a social psychologist at the University of Amsterdam who did not work with Stapel. Korean biologist Hwang Woo Suk became a national disgrace for faking a series of reports that claimed to show his lab had created human stem cells through cloning. And German physicist Jan Hendrik Schön prompted much hand-wringing among scientists after it was discovered that the semiconductor researcher falsified his results in at least 17 papers.
"But what shocks me" about the Stapel case, Van Kleef said, "is indeed the amount of planning and scheming involved."
Certainly in academia, the pressure to publish can be enormous, said Leslie John, a behavioral researcher at Harvard Business School.
"It's very competitive to get into top journals," John said. "There's these sort of incentives to produce clean-looking results."
Stapel's results, however, were too clean, and they seemed to support his initial hypotheses too well.
"Maybe he was originally driven by these pressures, but after he succeeded once, he was amazed at how effortless it was," said George Loewenstein, a professor of economics and psychology at Carnegie Mellon University. "No one questioned the results, and then he got huge amounts of positive feedback for what he had done. So it was just kind of irresistibly tempting for him to do it again."