Hilke Plassmann, a German scientist, has conducted original experiments that could revolutionize our understanding of how we react to injustice and impatience. An economist turned neuroscientist, she is particularly interested in the link between the microbiota and our decision-making.
The professor at the European Institute of Business Administration (Insead), who conducts her research within the "BEND team: belief and decision-making" of the Brain Institute (ICM) in Paris, will present her work at the Paris-Saclay Summit, an event organized by Le Point on February 12 and 13.
In a recent experiment, Plassmann and her team gave one group of volunteers a mixture of probiotics and prebiotics for seven weeks, while another group received a placebo. Both groups maintained the same diet. They then conducted various decision-making tests before and after the intervention.
The results were surprising. Those who received the symbiotic mixture became less "rational" from an economic standpoint. They showed more sensitivity to injustice and made less financially advantageous choices. They also became less patient.
Plassmann explains that the "rationality" they are referring to is defined by classic economic theories. For example, in their tests, participants had to choose between receiving a small sum immediately or a larger sum later. Or they had to react to an unfair distribution of money.
This is the first study to demonstrate this potential link between microbiota and decision-making in humans. Previous studies were primarily conducted on mice or were simply observational in humans. Plassmann emphasizes that this is just the beginning of these discoveries.
Plassmann believes that there are several possible communication pathways between our gut and our brain: the microbiota itself, hormones, neurotransmitters such as dopamine and serotonin, direct neural communication via the vagus nerve, and the immune system. This is an area that is still being actively explored.
While Plassmann's research suggests that the microbiota may influence certain traits like impatience, she emphasizes that it does not necessarily affect personality. She recommends a diverse diet rich in vegetables, fruits, and fiber to maintain a healthy gut microbiota.