The Mind of a Con Man

Yudhijit Bhattacharjee, New York Times, April 26, 2013

One summer night in 2011, a tall, 40-something professor named Diederik Stapel stepped out of his elegant brick house in the Dutch city of Tilburg to visit a friend around the corner. It was close to midnight, but his colleague Marcel Zeelenberg had called and texted Stapel that evening to say that he wanted to see him about an urgent matter. The two had known each other since the early ’90s, when they were Ph.D. students at the University of Amsterdam; now both were psychologists at Tilburg University. In 2010, Stapel became dean of the university’s School of Social and Behavioral Sciences and Zeelenberg head of the social psychology department. {snip}

Zeelenberg, a stocky man with a shaved head, led Stapel into his living room. “What’s up?” Stapel asked, settling onto a couch. Two graduate students had made an accusation, Zeelenberg explained. His eyes began to fill with tears. “They suspect you have been committing research fraud.”

Stapel was an academic star in the Netherlands and abroad, the author of several well-regarded studies on human attitudes and behavior. That spring, he published a widely publicized study in Science about an experiment done at the Utrecht train station showing that a trash-filled environment tended to bring out racist tendencies in individuals. And just days earlier, he received more media attention for a study indicating that eating meat made people selfish and less social.

His enemies were targeting him because of changes he initiated as dean, Stapel replied, quoting a Dutch proverb about high trees catching a lot of wind. When Zeelenberg challenged him with specifics—to explain why certain facts and figures he reported in different studies appeared to be identical—Stapel promised to be more careful in the future. As Zeelenberg pressed him, Stapel grew increasingly agitated.

Finally, Zeelenberg said: “I have to ask you if you’re faking data.”

“No, that’s ridiculous,” Stapel replied. “Of course not.”


That same day, Stapel drove to the University of Groningen, nearly three hours away, where he was a professor from 2000 to 2006. The campus there was one of the places where he claimed to have collected experimental data for several of his studies; to defend himself, he would need details from the place. But when he arrived that afternoon, the school looked very different from the way he remembered it being five years earlier. Stapel started to despair when he realized that he didn’t know what buildings had been around at the time of his study. Then he saw a structure that he recognized, a computer center. “That’s where it happened,” he said to himself; that’s where he did his experiments with undergraduate volunteers. “This is going to work.”

On his return trip to Tilburg, Stapel stopped at the train station in Utrecht. This was the site of his study linking racism to environmental untidiness, supposedly conducted during a strike by sanitation workers. In the experiment described in the Science paper, white volunteers were invited to fill out a questionnaire in a seat among a row of six chairs; the row was empty except for the first chair, which was taken by a black occupant or a white one. Stapel and his co-author claimed that white volunteers tended to sit farther away from the black person when the surrounding area was strewn with garbage. Now, looking around during rush hour, as people streamed on and off the platforms, Stapel could not find a location that matched the conditions described in his experiment.

“No, Diederik, this is ridiculous,” he told himself at last. “You really need to give it up.”

After he got home that night, he confessed to his wife. A week later, the university suspended him from his job and held a news conference to announce his fraud. It became the lead story in the Netherlands and would dominate headlines for months. Overnight, Stapel went from being a respected professor to perhaps the biggest con man in academic science.

I first met Stapel in the summer of 2012, nearly a year after his dismissal from Tilburg. {snip}

When Stapel and I met for lunch in Antwerp, about a 50-mile drive from Tilburg, investigating committees at the three universities where he had worked—Amsterdam, Groningen and Tilburg—were in the process of combing through his several dozen research papers to determine which ones were fraudulent. The scrutiny was meant not only to clean up the scientific record but also to establish whether any of Stapel’s co-authors, including more than 20 Ph.D. students he supervised, shared any of the blame. It was already evident that many of the doctoral dissertations he oversaw were based on his fabricated data.

Right away Stapel expressed what sounded like heartfelt remorse for what he did to his students. “I have fallen from my throne—I am on the floor,” he said, waving at the ground. “I am in therapy every week. I hate myself.” {snip}


Each case of research fraud that’s uncovered triggers a similar response from scientists. {snip} Still, the nature and scale of Stapel’s fraud sets him apart from most other cheating academics. “The extent to which I did it, the longevity of it, makes it extreme,” he told me. “Because it is not one paper or 10 but many more.”

Stapel did not deny that his deceit was driven by ambition. But it was more complicated than that, he told me. He insisted that he loved social psychology but had been frustrated by the messiness of experimental data, which rarely led to clear conclusions. His lifelong obsession with elegance and order, he said, led him to concoct sexy results that journals found attractive. “It was a quest for aesthetics, for beauty—instead of the truth,” he said. {snip}


Stapel lives in a picturesque tree-lined neighborhood in Tilburg, a quiet city of 200,000 in the south of the Netherlands. One afternoon last November, he sat in his kitchen eating a quickly assembled lunch of cheese, bread and chocolate sprinkles, running his fingers through his hair and mulling the future. The universities investigating him were preparing to come out with a final report a week later, which Stapel hoped would bring an end to the incessant flogging he had received in the Dutch media since the beginning of the scandal. The report’s publication would also allow him to release a book he had written in Dutch titled “Ontsporing” — “derailment” in English — for which he was paid a modest advance. The book is an examination of his life based on a personal diary he started after his fraud was made public. Stapel wanted it to bring both redemption and profit, and he seemed not to have given much thought to whether it would help or hurt him in his narrower quest to seek forgiveness from the students and colleagues he duped.


Several times in our conversation, Stapel alluded to having a fuzzy, postmodernist relationship with the truth, which he agreed served as a convenient fog for his wrongdoings. “It’s hard to know the truth,” he said. “When somebody says, ‘I love you,’ how do I know what it really means?” {snip}


On a Sunday morning, as we drove to a village near Maastricht to see his parents, Stapel reflected on why his behavior had sparked such outrage in the Netherlands. “People think of scientists as monks in a monastery looking out for the truth,” he said. “People have lost faith in the church, but they haven’t lost faith in science. My behavior shows that science is not holy.”

What the public didn’t realize, he said, was that academic science, too, was becoming a business. “There are scarce resources, you need grants, you need money, there is competition,” he said. “Normal people go to the edge to get that money. Science is of course about discovery, about digging to discover the truth. But it is also communication, persuasion, marketing. I am a salesman. I am on the road. People are on the road with their talk. With the same talk. It’s like a circus.” {snip}


In one experiment conducted with undergraduates recruited from his class, Stapel asked subjects to rate their individual attractiveness after they were flashed an image of either an attractive female face or a very unattractive one. The hypothesis was that subjects exposed to the attractive image would—through an automatic comparison—rate themselves as less attractive than subjects exposed to the other image.

The experiment—and others like it—didn’t give Stapel the desired results, he said. He had the choice of abandoning the work or redoing the experiment. But he had already spent a lot of time on the research and was convinced his hypothesis was valid. “I said—you know what, I am going to create the data set,” he told me.


The results were published in The Journal of Personality and Social Psychology in 2004. “I realized—hey, we can do this,” he told me.

Stapel’s career took off. He published more than two dozen studies while at Groningen, many of them written with his doctoral students. They don’t appear to have questioned why their supervisor was running many of the experiments for them. Nor did his colleagues inquire about this unusual practice.

In 2006, Stapel moved to Tilburg, joining Zeelenberg. Students flocked to his lab, and he quickly rose in influence. In September 2010, he became dean of the School of Social and Behavioral Sciences. He could have retreated from active research to focus on administration, but, he told me, he couldn’t resist the allure of fabricating new results. He had already made up the data for the Utrecht train-station study and was working on the paper that would appear in Science the following year. Colleagues sought him out to take part in new collaborations.

Stapel designed one such study to test whether individuals are inclined to consume more when primed with the idea of capitalism. He and his research partner developed a questionnaire that subjects would have to fill out under two subtly different conditions. In one, an M&M-filled mug with the word “kapitalisme” printed on it would sit on the table in front of the subject; in the other, the mug’s word would be different, a jumble of the letters in “kapitalisme.” Although the questionnaire included questions relating to capitalism and consumption, like whether big cars are preferable to small ones, the study’s key measure was the amount of M&M’s eaten by the subject while answering these questions. (The experimental approach wasn’t novel; similar M&M studies had been done by others.) Stapel and his colleague hypothesized that subjects facing a mug printed with “kapitalisme” would end up eating more M&M’s.

Stapel had a student arrange to get the mugs and M&M’s and later load them into his car along with a box of questionnaires. He then drove off, saying he was going to run the study at a high school in Rotterdam where a friend worked as a teacher.

Stapel dumped most of the questionnaires into a trash bin outside campus. At home, using his own scale, he weighed a mug filled with M&M’s and sat down to simulate the experiment. While filling out the questionnaire, he ate the M&M’s at what he believed was a reasonable rate and then weighed the mug again to estimate the amount a subject could be expected to eat. He built the rest of the data set around that number. He told me he gave away some of the M&M stash and ate a lot of it himself. “I was the only subject in these studies,” he said.


Rumors of fraud trailed Stapel from Groningen to Tilburg, but none raised enough suspicion to prompt investigation. Stapel’s atypical practice of collecting data for his graduate students wasn’t questioned, either. Then, in the spring of 2010, a graduate student noticed anomalies in three experiments Stapel had run for him. When asked for the raw data, Stapel initially said he no longer had it. Later that year, shortly after Stapel became dean, the student mentioned his concerns to a young professor at the university gym. Each of them spoke to me but requested anonymity because they worried their careers would be damaged if they were identified.

The professor, who had been hired recently, began attending Stapel’s lab meetings. He was struck by how great the data looked, no matter the experiment. “I don’t know that I ever saw that a study failed, which is highly unusual,” he told me. “Even the best people, in my experience, have studies that fail constantly. Usually, half don’t work.”

The professor approached Stapel to team up on a research project, with the intent of getting a closer look at how he worked. “I wanted to kind of play around with one of these amazing data sets,” he told me. The two of them designed studies to test the premise that reminding people of the financial crisis makes them more likely to act generously.

In early February, Stapel claimed he had run the studies. “Everything worked really well,” the professor told me wryly. Stapel claimed there was a statistical relationship between awareness of the financial crisis and generosity. But when the professor looked at the data, he discovered inconsistencies confirming his suspicions that Stapel was engaging in fraud.

The professor consulted a senior colleague in the United States, who told him he shouldn’t feel any obligation to report the matter. But the person who alerted the young professor, along with another graduate student, refused to let it go. That spring, the other graduate student examined a number of data sets that Stapel had supplied to students and postdocs in recent years, many of which led to papers and dissertations. She found a host of anomalies, the smoking gun being a data set in which Stapel appeared to have done a copy-paste job, leaving two rows of data nearly identical to each other.

The two students decided to report the charges to the department head, Marcel Zeelenberg. But they worried that Zeelenberg, Stapel’s friend, might come to his defense. To sound him out, one of the students made up a scenario about a professor who committed academic fraud, and asked Zeelenberg what he thought about the situation, without telling him it was hypothetical. “They should hang him from the highest tree” if the allegations were true, was Zeelenberg’s response, according to the student.

The students waited till the end of summer, when they would be at a conference with Zeelenberg in London. “We decided we should tell Marcel at the conference so that he couldn’t storm out and go to Diederik right away,” one of the students told me.

In London, the students met with Zeelenberg after dinner in the dorm where they were staying. As the night wore on, his initial skepticism turned into shock. It was nearly 3 when Zeelenberg finished his last beer and walked back to his room in a daze. In Tilburg that weekend, he confronted Stapel.


In late October, nearly two months after the scandal broke, the university issued an interim report portraying Stapel as an arrogant bully who cozied up to students in order to manipulate them. Stapel broke down after reading the personality assessment. “He was calling for his mother, he was freaking out,” Marcelle told me. “He was trying to get out of the window.” Stapel’s psychiatrist prescribed extra medication, and a friend made him promise Marcelle that he would not kill himself. To escape the media’s glare, he went to spend a few days with his brother in Budapest.


At the end of November, the universities unveiled their final report at a joint news conference: Stapel had committed fraud in at least 55 of his papers, as well as in 10 Ph.D. dissertations written by his students. The students were not culpable, even though their work was now tarnished. The field of psychology was indicted, too, with a finding that Stapel’s fraud went undetected for so long because of “a general culture of careless, selective and uncritical handling of research and data.” {snip}


When Stapel’s book came out, it got a mixed reception from critics, and it angered many in the Netherlands who thought it dishonorable of him to try to profit from his misdeeds. Within days of its release, the book appeared online in the form of PDFs, posted by those who wanted to damage his chances of making money. {snip}

I asked Zeelenberg how he felt toward Stapel a year and a half after reporting him to the rector. He told me that he found himself wanting to take a longer route to the grocery store to avoid walking past Stapel’s house, lest he run into him. “When this is all over, I would like to talk to him,” Zeelenberg said. “Then I’ll find out if he and I are capable of having a friendship. I miss him, but there are equal amounts of instances when I want to punch him in the face.”


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