The reason why humans need conspiracy theories is very simple. We are designed that way to keep us safe and to stop us ‘sleep walking’ into bad situations. It is more beneficial to be on our guard against malevolence than to worry about upsetting our fellow man by mistrusting them.
Steve Clarke an Australian philosopher proposed that conspiratorial thinking is maintained by the fundamental attribution error,
Fundamental Attribution Error states that people seriously overestimate the importance of dispositions, while underestimating the importance of situational factors in explaining the behaviour of others.
Dispositions —what motivates an individual to do or say something or their personality traits [individual differences in characteristic patterns of thinking, feeling, and behaving]
Situational Factors —such as random chance and social norms.
Clarke observed that this error is typical of conspiratorial thinking. People maintain and stick to their conspiratorial beliefs because to dispense with the conspiracy would be to discount human motives in events. – i.e. it CANNOT be a random freak nonoccurence or just plain chance
Clarke further suggested that the ultimate reason people make the fundamental attribution error is because all humans have evolved to do so.
The reason why humans need conspiracy theories
Humans evolved in tightly knit groups where understanding the motives of others was critical for the detection of malevolent intentions. The cost of making an error in identifying others’ insidious motives was small relative to the cost of not identifying such motives.
Therefore people are psychologically attuned to discount situational factors over dispositional factors in explaining others’ behaviour.