As a psychology major (and eventual psychologist), I remember this case well. Interestingly, while the bystander effect has stood up to time and research, the alleged apathy of the thirty-eight New Yorkers was challenged as some people did call police and it was unclear how much of the two-pronged attack bystanders actually witnessed.

Regardless of how many witnesses to Genovese's murder did nothing, research has shown that groups are less likely to help someone in trouble than a lone individual. But there's also been some good news! One 2010 meta-analysis on the bystander effect in Psychological Bulletin found that while groups are a little slower to help than individuals, this difference tends to disappear when it's clear there's a real emergency, and also when someone must physically intervene to help.