Why No One Called for Help

Explaining a bystander failure means combining attribution, norms, informational influence, and diffusion into one account of a single incident.

One incident on a crowded platform reconstructed completely: what each bystander could see, the ambiguity that made informational influence decisive, the norm of non-interference the setting supplied, the diffusion produced by the count of witnesses, and the attribution each witness later made about the others. Ends by naming the single intervention that research says would have broken the pattern, and why it works.