This type of brain activity can reveal how confident we are about decisions

Iconic English punk rock band The Clash is perhaps best known for their 1982 song Should I Stay or Should I Go. Besides the fact that it’s an incredibly catchy tune, that song has stood the test of time because it encapsulates a feeling everyone can relate to.

We’ve all been faced with a tricky decision at some point, and there’s nothing worse than feeling paralyzed by indecision.

At the end of the day, though, decisions are an unavoidable fact of life and a defining part of the human experience.

We’re all blessed by our ability to think for ourselves and make our own choices, but with that freedom also comes pressure. No one wants to make the wrong choice, but life often forces us to make choices we’re not all that confident about.

Researchers from the University of Bonn have discovered that the activity of specific nerve cells in the brain can reveal how confident an individual is about a decision or choice. This is a notable revelation, as it is the first time an actionable connection between brain activity and decision confidence has been uncovered.

These conclusions were reached via an experiment including 12 men and women, all of whom were suffering from a form of epilepsy. The epilepsy aspect of this study is important because these findings wouldn’t have been possible if it were not for the patients’ conditions. 

Normally, it’s considered unethical to study individual neurons in a living person. But, epileptic seizures always originate from the same brain region. With that in mind, one possible epilepsy treatment is to surgically remove that seizure-inducing brain area. To pinpoint the precise “defective” location that should be surgically removed, doctors must implant several ultra-fine electrodes in the patient’s temporal lobe.

That’s what happened to each of the participants in this study. However, besides just revealing the origin point of their epileptic seizures, the electrodes also provided groundbreaking new data on individual nerve cell activity during decision making

Somewhat humorously, while researchers were investigating one aspect of decision making with this experiment, they weren’t trying to uncover a connection between choice confidence and neural activity. Whenever anyone makes a choice between multiple options, their mind automatically assigns a “subjective value” to each option.

“There is evidence that this subjective value is also reflected in the activity of individual neurons,” says Dr. Florian Mormann, a professor at the University of Bonn’s Department of Epileptology, in a release. “The fact that we instead came across this connection between fire behavior and decision confidence surprised even us.” 

What was the experiment? When it comes to decisions, there’s perhaps no choice people agonize over more on a daily basis than the eternal question of what to eat. 

“We showed them photos of two different snacks, for example a chocolate bar and a bag of chips,” Dr. Mormann explains. “They were then asked to use a slider to indicate which of these alternatives they would rather eat.”

The further each participant moved the slider from the center toward either the right snack or left snack indicated how confident they were feeling about their food choice. 

This didn’t just happen once. Each participant was shown an astounding 190 different snack pairings. Meanwhile, as participants were making their choices, the electrodes in their brains recorded the activity of 830 nerve cells located in their temporal lobes.

“We discovered that the frequency of the electrical pulses in some neurons, in other words their ‘firing rate’, changed with increasing decision confidence,” Alexander Unruh-Pinheiro, a colleague of Dr. Mormann, notes. “For instance, some fired more frequently, the more confident the respective test person was in their decision.”

The more confident a participant felt about their snack choice, the more these temporal lobe neurons “fired.”

The temporal lobe is responsible for both the creation and maintenance of memories. So, the study’s authors speculate that our brains don’t just keep track of our decisions, but also take note of how confident we were feeling about that choice at the moment.

“It is possible that we not only store what decision we made, but also how confident we were in it,” Dr. Mormann adds. “Perhaps such a learning process saves us from future wrong decisions.”

Considering how far modern science and medical understanding has come, it speaks to the complexity of the human mind that we’re still making new, unexpected discoveries today. Our decisions define us, and there’s an entire world of neurological processes facilitating those decisions in ways we’re just now starting to fully grasp. 

The full study can be found here, published in Current Biology.