Between a glass of fruit juice now and a glass of champagne, what do you choose? Do you find it hard to resist immediate pleasures or do you prefer to expect even greater joy? We are bound to face this dilemma on a daily basis. The Inserm team led by Mathias Pessiglione wanted to know why we sometimes give in to temptation.
The discovery of the mechanisms in play can make it possible to understand a lot of things that have an impact on our health, for example why we eat too much fat and sugar while we are exposed to the cholesterolor overweight or why we continue to smoke so much when we know perfectly long-term risks.
The French study, published in the journal Plos Biology, lifts the veil on these a priori irrational choices. In fact, they would find their origin in the dorsolateral region of the prefrontal cortex. This region of the brain plays a role in controlling behavior.
Alzheimer’s disease leads to temptation
During several experiments, the researchers subjected an MRI of the brain to a set of volunteers. They had to choose between an immediate financial gain, 10 euros for example, or a larger gain later (11 euros tomorrow). Some choices seemed more difficult to make because they appealed to the imagination. It was about choosing an immediate gift visible in a photo or a more interesting gift but in a more distant future and more difficult to imagine.
The same tests were done on patients with Alzheimer’s.
It was clear that the choice of future rewards is associated with the activity of the prefrontal cortex. Alzheimer’s patients preferred immediate satisfaction, since their poor memory makes them unable to imagine future pleasures. “This is because the hippocampus is needed to imagine future situations with a wealth of detail that makes them attractive enough,” says Dr Pessiglione.
