Our miserly "reptilian brain" affects our financial decisions

Published 2013-08-22 00:00. Updated 2014-10-29 10:46Denna sida på svenska

It is easier to be generous in theory than it is in practice. In a new study published in the journal Social Cognitive and Affective Neuroscience, researchers show that there is a difference.

We are often more generous when dealing with hypothetical payments than we are with actual ones. To examine what happens in the brain when we take genuine decisions as opposed to imaginary ones, the researchers split 38 participants into two groups and asked them to make decisions on different suggested donations to charity while measuring their brain activity. One group of participants were asked to respond as if real money was involved, on the understanding that they would not actually be required to pay themselves; the other group were told that one of the charities they said yes to would be randomly selected for an actual donation.

"As far as we know, this is the first study to demonstrate a difference in brain signalling when we take real and hypothetical financial decisions," says lead author Dr Katarina Gospic, neuroscientist at the Department of Clinical Neuroscience. "What we found was that the amygdala was more active when we take real decisions than when we take hypothetical ones."

However, even if spending money hurts the wallet, we do it anyways. There are situations when we choose to spend money without personal gain, such as when donating to charity. In such cases we have to regulate the signals coming from the amygdala and feel some form of reward at the same time.

"When we examined the brain, we saw that real situations involving donating to charity are accompanied by activity in the rostral anterior cingulate cortex (rACC), the structure in the brain that can inhibit signals from the amygdala," says Dr Gospic. "This type of activity indicates that we are trying to repress the 'stinginess' signals in order that we can make the decision to donate. As the participants opted to donate, the striatum, which is the brain's reward structure that motivates us to act, was also activated."

Study leader was Professor Martin Ingvar. The research was financed by grants from the Swedish Research Council, the Osher Centre for Integrative Medicine at Karolinska Institutet, the Stockholm County Council, the Knut and Alice Wallenberg Foundation and Vinnova (the Swedish governmental agency for innovation systems).


Altruism costs-the cheap signal from amygdala.
Gospic K, Sundberg M, Maeder J, Fransson P, Petrovic P, Isacsson G, et al
Soc Cogn Affect Neurosci 2014 Sep;9(9):1325-32