bystander effect 

When witnessing a situation of an victim and 'incriminator', the degree of responsibility the witness has in helping the victim or stopping the 'crime' in progress. The degree of responsibility usually depends on three criteria; 1. Whether the victim is deserving of help, 2. The competence of the bystander, 3. The relationship between the bystander and the 'victim'. The bystander can intervene in usually two different ways; direct intervention, or, calling authorities.

I saw an old lady getting her purse taken by some thug, i just stood by and watched... later i felt confused and guilty. The feeling i felt could be described as the bystander effect

bystander effect by stevo142 July 20, 2013

By Stander Effect 

To become paralyzed, or not really knowing what to do, being scared and just watching.

Man: What do you call this when you see for example, a man is beating the hell out of his wife and you do not know what to do?
*out of nowhere from awkward silence
CB: Uhm, By Stander effect!
Man: Correct, what does it mean?
CB: Uhm *thinks, like your paralyzed or don't know what to do.

By Stander Effect by CBystander October 14, 2011