Brain basics: Life is the sum of all your choices (A. Camus)

Decision-making is a broad discipline studied by economists, philosophers, and historians. Neuroscientists more recently started studying it.

This post is also available in Dutch.

This blog is part of this year’s summer series called Brain basics, in which we dive into the general functions and development of our brains.

Which gelato flavor should I choose when I’m queueing at Vincenzo ijs? Facebook or Instagram?  Since we make these kinds of decisions every day, they might seem like easy tasks for our brains. Decision-making is the cognitive process of acquiring knowledge and understanding through actions or our senses that leads to an action selection or a thought, which can be rational or irrational. With decision-making, we aim to optimize the outcome of our actions, adapting our strategy to the changes and challenges of our environment.

Decision-making is a simple idea, but how do we study it?

Scientists study decision-making by recording the brain activity in animals and humans while they make decisions. For example, electrodes record the activity in the brain of rodents when they choose among options, like which route to take in a maze. Most of the time, it’s not possible to put electrodes in humans’ brains to record the activity directly. Instead, we can use techniques like functional magnetic resonance imaging (fMRI, click here to see how it works). With fMRI, we can record how the activation changes in different parts of the brain when people perform decision tasks while lying in an MRI scanner.

Brain areas involved in decision-making

Almost two decades ago[HO1] , neuroscientists found out that the brain areas involved in decision making are the dorsal anterior cingulate cortex (ACd), orbitofrontal cortex (OFC), and prefrontal cortex (PFC). [HO2] When someone makes their own voluntary decision, the activation levels in the ACd increase while they decrease in the OFC. If the experimenter guides the choice, we see that the pattern of activation is the other way around. One key aspect of decision-making is the flexibility to adapt our behavior based on the feedback we receive. A group of researchers in Oxford discovered that the anterior cingulate cortex (ACC) of monkeys is implicated in action selection using reinforcement. This means that, when their ACC is damaged, monkeys are not able to use past information to guide the decision-making process.

Emotions in decision-making

Some of us might think that humans act in a very goal-oriented and[KM(3]  rational way. But, if the Bridget Jones movies ever taught us anything, it is that emotions count. Have you ever followed a gut feeling that turned out to be the correct decision? This might be explained by the somatic marker hypothesis[HO4] .This theory suggests that emotional processes can (consciously or unconsciously) have an impact on decision-making by creating somatic markers. Somatic markers are changes in our bodies, like increases in our heart rates or skin conductance. The researchers noticed that patients with damage in brain areas involved in decision-making and emotions (like the amygdala and PFC) were more likely to make bad decisions in a gambling task. In line with the somatic marker hypothesis, people without damage began to show skin conductance responses (the result of sweating and an indicator of impulsive attitudes) before a risky choice. In contrast patients with lesions never developed anticipatory skin conductance responses. This study aimed to prove that the somatic markers encoded during past experiences can bias our future decisions.

As decision-making is a complex process that involves a lot of brain areas, there is still a lot to be learned about it. Despite that, decision-making is crucial not only for humans but for all the other species in the animal kingdom.

In the upcoming blogs of this series we’ll dive further into the anatomy, the development and the different functions of our brains


Author: Francesca Abela

Buddy: Maartje Koot

Editor: Helena Olraun

Translator: Judith Scholing

Editor translation: Floortje Bouwkamp

Picture credits: Javier Allegue Barros from Unsplash

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