Acar crash woke john from his afternoon nap. when he looked out his apartment window, he saw several people milling around two smashed cars. he decided not to dial 911 because he assumed someone had already called. john's reaction is an example of (a) bystander effect (b) foot-in-the-door phenomenon (c) fundamental attribution errors (d) frustration-aggression principle

John's reaction is an example of the bystander effect.

Explanation:

A scientific study that states that when an individual is less likely to offer help to the victim when a number of people are present. This is known as the bystander effect.

According to this theory, more the number of people standing, that is, more the number of bystanders, less are the chances of an individual to offer help to the victim.

As given in the example, John assumed that one of the bystanders would have called the police, so he decided not to make a call, is an example of the bystander effect.