The Princeton Engineering Anomalies Research (PEAR) was a research program at Princeton University that studied parapsychology. It was started in 1979 by Robert G. Jahn, who was then the Dean of Engineering. PEAR conducted scientific studies on two main topics: psychokinesis (PK) and remote viewing. Because the topics were controversial, the program had a difficult relationship with Princeton University. Some people at the university thought it was embarrassing. Critics said the program did not follow strict scientific rules, used methods that were not good, used statistics incorrectly, and called it pseudoscience. PEAR closed in February 2007 and became part of the "International Consciousness Research Laboratories (ICRL)."

Parapsychological experiments with random event generators

PEAR used electronic devices called random event generators (REGs) to study whether people could influence the random numbers these machines produced using psychokinesis, or the supposed ability to affect physical objects with the mind. Most experiments used a small electronic REG, but some tested a large, wall-mounted machine similar to a pachinko game, where balls bounce down through a series of paths.

In 1986, PEAR shared results from seven years of experiments involving many trials where participants tried to influence random number generators. The effects observed were very small, ranging from 0.1% to 1%. While the results reached a statistical significance level of P<0.05, critics raised concerns about ethical issues, flaws in the experiments, and the value of studies with only slight statistical significance. The baseline used to compare results was not adjusted properly, which some PEAR researchers linked to the operators’ desire to achieve a good baseline and suggested the random number generator might not have been truly random. One individual, believed to be a PEAR staff member, participated in 15% of the trials and contributed to half of the observed effects.

James Alcock, in a review, pointed out problems with the experiments, including poor controls, incomplete documentation, and the possibility of fraud. He also noted that data selection and optional stopping were not ruled out and concluded there was no evidence the results were due to paranormal causes.

C. E. M. Hansel, a psychologist who reviewed early PEAR experiments, stated that the studies lacked proper control groups, independent replication, and detailed descriptions. He noted that little information was provided about the experiments’ design, participants, or testing conditions. Physicist Milton Rothman criticized the experiments for starting with an unrealistic assumption and ignoring established scientific principles.

PEAR’s findings have been criticized for being hard to reproduce. For example, two German organizations could not replicate PEAR’s results, nor could PEAR itself reproduce its own findings. York University’s Stan Jeffers also failed to replicate the results.