When evil happens, we tend to take an egocentric approach to analysis. We look for the bad apples.

In his TED talk "The psychology of evil" Philip Zimbardo explains how otherwise good apples can turn bad, when placed in a bad barrel, created and sustained by bad barrel makers.

apple, barrel and barrel maker

From an organisational culture perspective, the three factors that affect human behaviour are:

1. The type of people we recruit.
2. The situations they work in.
3. The attitudes of the leadership.

Simply recruiting good people, or creating good processes/environments, or installing ethical/collaborative/kind leaders are not enough on their own.