Two things: - Cameras may have caused the Hawthorne effect: https://en.wikipedia.org/wiki/Hawthorne_effect - The article (the news one, haven't read the original yet) talks about the increase of probability that some bystander will act, with increase in group size. The bystander effect study talks about the decrease of probability that a particular individual will act, with decrease in group size. These two things ma…
I believe the study did show that. I heard an interview with one of the authors on the radio (so my memory may be faulty).
So I don't think it really debunked the bystander effect, rather he made a point along the lines of, 'it doesn't really matter, the more people present means it's the more likely that one of them intervenes'.