When an assailant raped and murdered New Yorker Kitty Genovese in 1964, The New York Times reported that dozens of people witnessed the attack and did nothing to stop it.

But in the early 2000s, another Times piece found the claims in the 1964 article were exaggerated and sensationalized. Probably less than 10 people had knowledge of the attack, with three of them intervening.

But at the time, the tragedy and the supposed apathy that surrounded it, led to a burgeoning field looking into a possible Bystander Effect, including the Smoke Filled Room study of 1968. Social psychology researchers Bibb Latane and John Darley ran a series of experiments testing their hypothesis that when other people are around, bystanders are less likely to intervene.

In the best-known of their studies, the pair recruited subjects to fill out a questionnaire. The first group consisted of subjects who answered questionnaire by themselves, while the second group involved several persons filling out the form.

A few minutes into the experiment, thick smoke pored through a vent. Those by themselves, for the most part, left the room immediately and informed Latane and Darley.

Subjects in the second group, however, responded differently. Only one was an actual subject, the other persons were in on the experiment and had been instructed to take no action. Most of the time, the subject likewise failed to act.

In all, 75 percent of solo subjects intervened in the smoke, while just 10 percent of the subjects surrounded by confederates did. This seemed to confirm Latane and Darley’s hypothesis. Similar experiments yielded similar results, though not all of them as pronounced. But the differences were consistent enough that the duo concluded that there was a casual effect to the number of persons present and the likelihood of intervention.

But then in 2019, publications reported that the Bystander Effect was largely nonexistent, that a review of public conflicts showed that most people do intervene.

This research focused on public altercations captured on video. More than 1,200 conflicts were examined, in Lancaster, UK, Amsterdam, and Cape Town. In each city, intervention occurred nine times out of 10. Further, stepping in was most likely to occur if there were more bystanders.

As to the opposite conclusion being reached in the Smoke Filled Room studies, that can be explained by the study’s flawed methodology. Other than a lone subject, participants were instructed to not act. Had smoke began filling a room of 20 persons not in on the charade, some of them would have almost certainly taken action, as the results of the 1,200 public altercations demonstrate.

Skeptoid’s Brian Dunning wrote that a better-designed experiment would have had no confederates and, indeed, that would have produced a more authentic result. The test, he noted, served as an experiment on peer pressure, but not the bystander effect it was presuming to examine.