“Why is denial such a natural tendency? Psychologists have a name for the root cause which has become famous enough that many non-psychologists will recognise the term: cognitive dissonance. Cognitive dissonance describes the mind’s difficulty in holding two apparently contradictory thoughts simultaneously.
This odd phenomenon was first pinned down in an ingenious laboratory experiment half a century ago. Leon Ferstinger and James Carlsmith asked their experimental subjects to perform a tedious task – emptying and refilling a tray with spool, using one hand – for half an hour. On some plausible-sounding pretext they then offered a third of their subjects $1 – a small sum even in 1959, about an hour’s wage – to tell the next experimental subject (actually an actress) what a great time they’d had stacking spools onto trays for half an hour. They offered another third a more substantial sum, $20, half a week’s typical wages, to do the same thing. The remaining third went straight to the questionnaire which all subjects finally filled in, asking if they had enjoyed themselves.
Unsurprisingly, most people said they hadn’t. Yet there was a very odd exception: the students who’d been asked to reassure this stranger about what fun they’d been having, and who’d been paid only a dollar to do so, were much more likely to tell the experimenters that they’d enjoyed themselves. The unconscious cognitive process seems to be: ‘with very little incentive, i told this girl I enjoyed myself. So, I guess I must have enjoyed myself, right?’ By contrast the one’s who’s been paid $20 seemed more able to separate the events in their minds: ‘Hey, if the pay is good, who wouldn’t tell a white lie?’.”
So, the mind does not like to hold multiple, contradictory thoughts simultaneously. When such a situation arises, the mind strives for consistency by reducing the conflict.
In the experiment outlined above, the third of subjects who were only paid a dollar were forced into a state of cognitive dissonance. They simultaneously knew that they had not enjoy the task and that they had told a candidate that they had. As a response to this, these candidates reduced their internal conflict by reconciling their memory of events with what they had told the actress following following the task.