The road of life is full of flattened squirrels that couldn’t make a decision—and scientists from the University of Zurich think they know why those choices were such a struggle (for humans, anyway).
The team set out to explore why some people can never make up their minds, especially when it comes to food. Using a method known as transcranial alternating current stimulation (tACS), which allows scientists to stimulate the brain non-invasively, the researchers asked 86 participants to make decisions about food. These decisions were either about preferences (e.g. “I like cherries better than melons”) or were objective sensory-based decisions (“A melon is larger than a cherry”).
While these decisions were being made, the researchers used tACS to stimulate or disrupt signals between two areas indicated in subjective decision-making in primates: the medial–prefrontal and parietal cortices. Subjects did not realize they were being stimulated.
In the end, the research confirmed that decision-making doesn’t rely on one brain area telling you what to do, but on the communication between two separate areas, as the tACS was shown to affect decision-making abilities. However, decisions were not made more stable by intensifying the communication between the two regions; only disruptions bore fruit, as participants were made less likely to stick with their food preference decisions.
“We discovered that preference-based decisions were less stable if the information flow between the two brain regions was disrupted. Our test subjects were therefore more indecisive. For the purely sensory decisions, however, there was no such effect,” explained Professor Christian Ruff, a neuroeconomist from the University of Zurich, in a press release. “Consequently, the communication between the two brain regions is only relevant if we have to decide whether we like something and not when we make decisions based on objective facts.”
With this discovery, a new therapeutic technique may arise for those who suffer from a high degree of impulsiveness and indecisiveness in the aftermath of brain disorders. However, this is still years away.
The full paper can be found in Nature Communications.
(Image credit: Thinkstock)
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