Laura Steenbergen met her scientific mentor as an undergraduate. In 2009, she began a bachelor’s degree in psychology at Leiden University in the Netherlands and did her undergraduate thesis under the supervision of Lorenza Colzato, a cognitive psychologist with a prolific academic output. Steenbergen soon realized she enjoyed research, and with Colzato’s help, she transitioned into a master’s degree, then a PhD. They made a good team, Steenbergen thought.

Steenbergen says she found it hard at first as a student with hardly any research experience to know whether Colzato’s research practices were unusual. Steenbergen had always appreciated that her mentor worked efficiently. Sometimes, for example, according to Steenbergen, Colzato would say that she had obtained ethics approval from the university for studies involving research participants after just one or two weeks. And once Steenbergen started talking to participants herself to collect data, she noticed that Colzato would report the findings in their papers for substantially fewer people than had actually participated in a research project, without specifying why some people’s results were omitted from the data analysis.

According to Steenbergen, Colzato dismissed her concerns and would instead question whether science was an appropriate choice for the PhD student — a painful thing for Steenbergen to hear because she knew she wanted a scientific career.

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Eventually, after speaking to another PhD student and a postdoctoral researcher in Colzato’s laboratory, Steenbergen realized that her concerns weren’t all in her head. It wasn’t clear what the junior researchers could do about it, however. The Cognitive Psychology Unit within the Institute of Psychology where they worked was headed by Colzato’s husband, Bernhard Hommel. Because of this, they felt that they had limited recourse to other colleagues, Steenbergen says.

Steenbergen continued to work with Colzato, starting a one-year postdoc position in 2016. She explains that, because she completed her PhD in only two years, she had no time to consider jobs elsewhere.

After that, she worked briefly at other universities, including the University of Amsterdam and Ohio State University in Columbus, exposing her to other workplaces and making her realize that Colzato’s research practices were unusual.

Data doubt

In 2018, she returned to Leiden University as an assistant professor. It was at that point that new students working with Colzato asked Steenbergen why data were being deleted, she says.

This prompted her and a former colleague to report their concerns about research integrity to Sander Nieuwenhuis, the head of the Cognitive Psychology Unit (by this stage, Hommel had moved on from that position). In 2019, Philip Spinhoven, scientific director of the Institute of Psychology, submitted an internal complaint regarding Colzato and a suspected violation of academic integrity, based on what he had been told.

The university’s Academic Integrity Committee conducted an investigation, considering four allegations in total. In its 27-page ruling in 2019 (in which names are redacted), it stated: “The Defendant has repeatedly selectively omitted research results and has not reported this or given reasons for it. She has thus violated academic integrity.”

The committee also acknowledged that the group’s young, less experienced researchers were not responsible for the violations.

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Colzato was suspended by the university in 2019 and then resigned. In 2020, a journal article co-authored by her and Steenbergen was retracted¹, followed by a second in 2021². Data manipulation was given as the reason in each case. The retractions were a relief to Steenbergen, although she still struggled with anxiety over her decision to report the problems, saying: “It feels like I filed a process against my scientific mother.”

In Colzato’s response to a 2019 Retraction Watch article about the outcome of the misconduct hearing, she described herself as a scapegoat, and maintained that she had experienced “wonderful” working relationships with Steenbergen and the colleagues who had raised the concerns.

She admitted obtaining blood from human participants when approval had not been granted by Leiden University’s Medical Ethics Review Committee, but in the Retraction Watch article points out that Steenbergen carried out the procedures.

Steenbergen says that power dynamics were in play around the blood collection, and that “being a PhD student, it feels like you have to do that”.

Taking action

Steenbergen says the case has exacted a personal toll. During the investigation, when all the publications she had co-authored with Colzato came under scrutiny, “I felt frozen in science, because who’s going to take you seriously if everything about your work is suspicious? So I needed things to be open.”

On returning to work after a period of absence in 2023 and seeing that her PhD dissertation had recently been downloaded by others, she wanted to take action but wasn’t sure how to proceed. There are examples of authors choosing to retract their own papers and of dissertations being retracted against the authors’ wishes. But Steenbergen says she had no model for acknowledging the issues in her own dissertation.

On talking to other faculty members, she proposed to print “retracted” over the two chapters of her nine-chapter dissertation that had been affected by Colzato’s misconduct, and to write a cover note for the document. “I didn’t want to erase it or change it,” Steenbergen explains. She remembers thinking, “It’s more constructive if I use it.”

Steenbergen says the university was supportive. In October 2024, two months after she made her proposal, the dissertation was corrected with retractions for two chapters and an expression of concern for another chapter on which a journal publication was based.

“This is unprecedented in my experience,” says Dorothy Bishop, a retired developmental neuropsychologist at the University of Oxford, UK, who writes about scientific integrity. “It looks like Steenbergen did the right thing, which can’t have been easy for her.”

Bishop says that this case illustrates the potentially catastrophic effect of a principal investigator’s research misconduct on an early-career researcher in their lab, adding: “Many leave the field,” which is especially likely when universities do not back whistleblowers.