New research, published in the Journal of Neuroscience, has revealed that two different parts of the brain are activated, and compete with each other, when we make decisions based on past experience. They can cause us to overvalue experiences that end well despite starting badly, and undervalue experiences that end badly despite starting well - even if both are equally valuable overall.
“When you’re deciding where to go for dinner, for example, you think about where you’ve had a good meal in the past. But your memory of whether that meal was good isn’t always reliable - our brain values the final few moments of the experience more highly than the rest of it,” said Dr Martin Vestergaard, a researcher in the University of Cambridge’s Department of Physiology, Development and Neuroscience, who led the study.
“If we can’t control our in-built attraction to happy endings, then we can’t trust our choices to serve our best interests.”
The part of the brain called the amygdala works out the ‘objective value’ of an experience - the overall tastiness of a three-course meal, for example. Meanwhile a brain region called the anterior insula was shown to ‘mark down’ our valuation of an experience if it gets gradually worse over time.
The further back in time an experience was, even if still quite recent, the less weight it carries in making the next decision. The researchers call it the ‘happy ending effect’: we tend to make decisions based on previous experiences that ended well, irrespective of how good the experiences were overall.
Reproduced courtesy of the University of Cambridge