• Emilia Lambert

Learning About Your Brain: The Neurobiology of Decision Making

Think of a time that you had to make an important decision. Many different areas of your brain were working together to make the best decision. Let us take a closer look at the brain regions responsible for helping us to make these decisions.


Brain Regions Associated with Decision Making


The Frontal Cortex: The frontal lobe handles making plans and judgments. These responsibilities include decision making.¹


The Orbitofrontal Cortex: This is the part of the frontal cortex that communicates with the reward centers of the brain in the striatum. Patients with lesions to this part of the brain have difficulty showing empathy and altering their decisions to avoid unfavorable outcomes.² Studies on patients with damage to the ventromedial prefrontal cortex show that they have difficulty with understanding the long term consequences of their decisions.³


The Dorsolateral Prefrontal Cortex: This region of the frontal cortex helps to integrate sources of information. It maintains information from working memory and retrieves information from other associated cortex regions.Working memory refers to the information that you maintain in short term storage while your brain performs a task.


The Anterior Cingulate Cortex: This region of the prefrontal cortex helps to sort conflicting processes and reviews feedback from other areas of the brain. Imaging studies of this area show activation of the ACC in response to non-reward based decisions. It also responds to negative feedback.


The Basal Ganglia: This region of the brain performs many tasks, such as motor preparation and task switching. It has a large collection of neurotransmitters receptors for a chemical called dopamine.These receptors for dopamine allow the basal ganglia to help with reward-based learning and tasks. Research shows that cortical areas of the brain (discussed above) send connections to the basal ganglia.


---Ventral Striatum: This region is part of the basal ganglia. It helps moderate reward-based behavior and decision making. Damage to this area of the brain is associated with a lack of restraint and spontaneous behavior.


Amygdala: This part of your brain aids in emotional expression. It is especially critical for the expression of anger and aggression.This region helps with emotional processing during decision making.¹⁰


Cerebellum: This part of the brain is traditionally associated with the coordination of motor movements. Recent research has demonstrated that damage to this region of the brain can contribute to diminished performance on decision-making tasks.¹¹ This performance might be due to the temporal information that the cerebellum encodes. Damage to the cerebellum would impair this information making it difficult to understand the timing of events.¹² This skill is crucial to making the best decisions.


Neuroscientists make a distinction between risky and uncertain situations that require decision making. In a risky situation, you have all the information needed to analyze possible outcomes.
Illustration by Nadia Mokadem

How Do These Brain Regions Affect Decision Making?


Risk vs. uncertainty:


Neuroscientists make a distinction between risky and uncertain situations that require decision making. In a risky situation, you have all the information needed to analyze possible outcomes. In uncertain situations, some of the information necessary to decide may be unknown.¹³ An important assumption that the researchers in this area are making is the scale of the decisions. In a risky situation, they are assuming that it is a small scale decision. In an uncertain situation, they are assuming that it is a large scale decision.¹⁴


Researchers proposed that using calculations in risky situations should allow the best outcome. They suggested that heuristics can help make the optimal decision in an uncertain scenario.¹⁵


A heuristic is a model that the brain uses when it does not have all the information required to make a decision. It allows the brain to make an educated guess, although it can introduce bias. Examples of heuristics that humans use are the recognition heuristic and take-the-best heuristic.


In a decision where you apply the recognition heuristic, you are given two alternatives (say two different cities). One of the alternatives is familiar to you, and the other is new. Your goal is to decide which alternative is better when given a criterion.¹⁶ Using this heuristic, you will choose the one that you were familiar with as the higher-rated choice. Research shows that this heuristic involves more regions of your brain than only memory recall. Functional imaging of the brain also shows activation of the prefrontal cortex.¹⁷


In the take-the-best, you are familiar with both of the alternatives posed to you. This heuristic uses comparisons of the alternatives in your memory. You go through comparisons until you find something that differentiates the two alternatives. This differentiator allows you to estimate which alternative fits better.¹⁸ For example, you imagine two cities that you have heard of before. Your task is to determine which one has a larger population. You can use several criteria that you may remember about these cities to make an educated guess about which one has a larger population.


Impulsive vs. self-controlled decisions:


Some decisions allow you to choose between being impulsive or self-controlled. Impulsive decisions focus on smaller short-term gratification. Self-controlled decisions focus on long-term gratification.¹⁹ An example of this is financial decisions. You can make purchases now that are smaller and bring immediate joy (going out to a fancy dinner). You could also choose to save your money for a long-term goal (going on a nice vacation).


Research demonstrates that the brain relies on two different systems to make decisions. Conditions where researchers offered participants an immediate reward activated the limbic pathway (basal ganglia and ventral striatum). The researchers also found that the lateral prefrontal cortex was active in both conditions. This activity occurred regardless of the timing of the reward (immediate or delayed). They discovered that there is an interaction between the two systems. This interaction demonstrated more activation in one direction, depending on how the participant decides. If the participant chooses the delayed option, the lateral prefrontal cortex shows more activation.²⁰


Understanding how our brain makes decisions can help to inform our decision-making process. The next time you make a little decision in your life, take a moment to take a deep breath. This pause could be a good time to stop and appreciate all the parts of your brain that were influential in that decision.

References

  1. Myers, D. G. (2011). Myers' psychology for AP®. New York, NY: Worth.

  2. Broche-Pérez, Y., Jiménez, L. H., & Omar-Martínez, E. (2016). Neural substrates of decision-making. Neurología (English Edition), 31(5), 319-325.

  3. Bechara, A., Damasio, A. R., Damasio, H., & Anderson, S. W. (1994). Insensitivity to future consequences following damage to human prefrontal cortex. Cognition, 50, 1-3.

  4. Broche-Pérez, Y., Jiménez, L. H., & Omar-Martínez, E. (2016). Neural substrates of decision-making. Neurología (English Edition), 31(5), 319-325.

  5. Ibid.

  6. Gazzaniga, M. S., Ivry, R. B., & Mangun, G. R. (2019). Cognitive neuroscience: The biology of the mind (5th ed.). New York, NY: W.W. Norton & Company.

  7. Broche-Pérez, Y., Jiménez, L. H., & Omar-Martínez, E. (2016). Neural substrates of decision-making. Neurología (English Edition), 31(5), 319-325.

  8. Ibid.

  9. Myers, D. G. (2011). Myers' psychology for AP®. New York, NY: Worth.

  10. Broche-Pérez, Y., Jiménez, L. H., & Omar-Martínez, E. (2016). Neural substrates of decision-making. Neurología (English Edition), 31(5), 319-325.

  11. Ibid.

  12. Ibid.

  13. Volz, K. G., & Gigerenzer, G. (2012). Cognitive processes in decisions under risk are not the same as in decisions under uncertainty. Frontiers in Neuroscience, 6, 105.

  14. Ibid.

  15. Ibid.

  16. Ibid.

  17. Ibid.

  18. Ibid.

  19. Kalenscher, T., Ohmann, T., & Güntürkün, O. (2006). The neuroscience of impulsive and self-controlled decisions. International Journal of Psychophysiology, 62(2), 203-211.

  20. McClure, S. M., Laibson, D. I., Loewenstein, G., & Cohen, J. D. (2004). Separate neural systems value immediate and delayed monetary rewards. Science, 306(5695), 503-507.