According to Nathan DeWall and Roy Baumeister, it’s because we have an inbuilt psychological immune system that works tirelessly beneath our conscious awareness, tuning our mind to a more positive channel whenever we think about death.
In one study, dozens of students were asked to complete word stems like “jo_”, which can either be completed to become a positive word “joy” or a neutral word like “jog”. Students who had previously been asked to contemplate their own death were far more likely to form positive words than were other the students who’d been asked to contemplate a painful visit to the dentist. It seems thinking about death had somehow turned the students minds to positive words, a finding consistent with what psychologists call ‘terror management theory’ – our denial of morbid reality.
And yet this appeared to be a subconscious process – both the death and dentist contemplation students scored the same on a self-report mood questionnaire given to them between the contemplation task and the word completion task.
The finding was replicated in a second study using a word similarity task. Students were presented with a target word (e.g. joke) and had to say whether it was more similar to an emotionally related comparison word (e.g. sunbeam) or a semantically related alternative (e.g. speech). When it came to happy target words, but not fearful or sad ones, students who had thought about dying were far more likely to choose the emotionally related comparison word rather than the semantically related one, but no such effect was observed among the students who thought about the dentist – they were just as likely to pick the emotionally or semantically related words.
A final experiment demonstrated how counter-intuitive these findings are, and helped explain why we are so poor at predicting how events will affect us emotionally. Contrary to the actual results observed in the first two experiments, students asked to imagine the effects of contemplating death failed to predict that they would be more tuned to positive words, and they overestimated how badly their mood would be affected.
“Death is a psychologically threatening fact, but when people contemplate it, apparently the automatic system begins to search for happy thoughts,” the researchers said. “Moreover, this occurs immediately and outside of awareness”.
DeWall, C.N. & Baumeister, R.F. (2007). From terror to joy. Automatic tuning to positive affective information following mortality salience. Psychological Science, 18, 984-990.