I am seeing more and more where people are complaining about the filming of an attack and not intervening in it. People are claiming they would do something. But… I suspect many of the people who film these events without intervening think beforehand they would do something too.
Why they do not intervene is pretty well studied.
How could people just stand by and watch something this horrible happen to a young, innocent girl? Some have suggested that the eyewitnesses’ failure to report the incident likely resulted from a concern over being labeled as a snitch. Although this is possible, social psychological research on the bystander effect suggests a different cause – there were too many eyewitnesses present. The bystander effect refers to the fact that people are less likely to offer help when they are in a group than when they are alone. Research on this effect was inspired by a real-world account that seems hauntingly similar to the recent event in Richmond.Why Do We Help Less When There is a Crowd?: Less is More When it Comes to Bystanders. Burkley, Melissa. Psychology Today. Nov 04, 2009
One of the pieces is in the assessment of the situation. We tend to look to how others are reacting to a situation to decide whether to intervene. If no one else is, then we likely will not either. The fewer other witnesses there are, the less the inaction of others plays into our own. The article makes a great example of asking questions. I see it all the time where if the leaders do not ask, then no one else is.
The other piece is in how people feel responsibility. When there is a single person present, they feel wholly responsible. When there are more attending the event, that feeling diffuses among the additional people. With say, 10 people, each only feels about 10% responsible. A crowd watching an event is less likely to feel responsible for a negative outcome than a single person.
In the claims about being willing to act, I bet they all think of the scenario in terms of themselves being the sole witness to it where they would have to assess it without consideration of anyone else’s inaction causing them not to intervene and also where they would feel wholly responsible. I doubt any consider it from the more likely standpoint of there being multiple people in attendance and the Bystander Effect takes place.