The Neuroscience of Habits: How Subconscious Neural Activity Holds Control Over Our Daily Lives

by Aviram Nessim, April 8, 2023

Among the notable findings that Wendy Wood, a social psychologist at the University of Southern California, illuminated throughout her decades-long career is that an astonishing 43% of daily actions are enacted on the basis of habit (Wood et al., n.d.). A habit, or psychological disposition to repeat past behavior, is gradually acquired through repetition and is reinforced by desirable outcomes (Wood et al., 2021). Habits can be subdivided into a continuum of strength, where habits of weak and moderate strength are performed less frequently and/or in more variable contexts than strong habits (Lalley et al., 2009). To better understand the causation of both beneficial and harmful habitual behaviors, it is critical to consider the various facets, both at micro and macro levels, impacting human behavior. Fortunately, extensive psychological research has delved into the neural mechanisms responsible for habit formation and perpetuation by way of unconscious, automatic actions, thereby promising valuable insights into their development and propagation. With this in mind, this article seeks to investigate the interplay of habits with regards to cognitive neuroscience, providing a more nuanced comprehension of habitual behaviors, their potential implications, and feasible solutions to eradicate unnecessary behavior for greater individual and societal benefit.

Within the brain, two major neurotransmitters, dopamine and glutamate, serve as the backbone behind the neural mechanisms involved in the habituation process. Dopamine acts in reward-motivation learning, while glutamate functions in the formation and strengthening of neural connections. When accounting for common cases in which a behavior is associated with a reward (such as gratification upon consumption of unhealthy food), dopamine is released into the striatum, invoking a pleasurable response (Volkow et al., 2010). Over time, the gradual release of glutamate will strengthen neural connections that underpin the behavior, fostering its automaticity and reducing reliance on volitional thought (Gardner, 2011). Therefore, once a behavior is reinforced, its chances of reoccurrence increase. 

Aside from this, a larger group of subcortical structures known collectively as the basal ganglia are responsible for habit formation and maintenance. The basal ganglia consists of several nuclei, including the striatum, which is composed of the caudate nucleus and the putamen, in addition to the globus pallidus. The striatum is the primary site for habit formation, while the globus pallidus is affiliated with inhibiting habitual responses (Gu et al., 2020). With its extensive regulatory framework, the basal ganglia orchestrates a feedback loop, which serves to strengthen the conduct of the behavior in response to a particular cue or contextual stimulus.  To the basal ganglia, however, it is of least concern as to whether this stimulus is advantageous or deleterious; if a person habitually reaches for unhealthy food in times of stress, the basal ganglia will proceed to reinforce such conduct whenever they encounter analogous circumstances or experience a comparable degree of stress. This subsequently makes the behavior more likely to occur in the future, even in the absence of conscious thought or effort (Seger et al., 2011).

Although habits are largely involuntary (Marsch et al., 2014), they are capable of being altered through habit reversal training (HRT). The process entails pinpointing the cue that prompted the behavior and substituting it with a more preferable one (Heinicke et al., 2020). In the same case of a person habitually reaching for unhealthy food in stressful situations, a substitution attached to an alternative behavior, such as taking deep breaths, necessitates a deliberate attempt to supplant the automatic response with the forceful implementation of a new habit. 

The intrinsic nature of habit is one of ubiquity and omnipresence﹣a universal, primordial relic deeply embedded within every human. While old habits die hard, gaining an understanding of the neural mechanisms involved in habituation can lead to greater control over conscious decision-making and initiative-taking in our lives. Through the continuation of global research as well as driving home the ways habits intertwine with daily life, we can be driven towards a more conscious society and a far more empowered world. 


References

Gardner E. L. (2011). Addiction and brain reward and antireward pathways. Advances in psychosomatic medicine, 30, 22–60. https://doi.org/10.1159/000324065

Gu, B. M., Schmidt, R., & Berke, J. D. (2020). Globus pallidus dynamics reveal covert strategies for behavioral inhibition. eLife, 9, e57215. https://doi.org/10.7554/eLife.57215

Heinicke, M. R., Stiede, J. T., Miltenberger, R. G., & Woods, D. W. (2020). Reducing risky behavior with habit reversal: A review of behavioral strategies to reduce habitual hand-to-head behavior. Journal of applied behavior analysis, 53(3), 1225–1236. https://doi.org/10.1002/jaba.745

Lalley, P., Van Jaarsveld, C., Potts, H., & Wardle, J. (2009). How are habits formed: Modeling habit formation in the real world. European Journal of Social Psychology, 40(6), 998-1009. https://onlinelibrary.wiley.com/doi/10.1002/ejsp.674

Marsch, L. A., Guarino, H., Acosta, M., Aponte-Melendez, Y., Cleland, C., Grabinski, M., Brady, R., & Edwards, J. (2014). Web-based behavioral treatment for substance use disorders as a partial replacement of standard methadone maintenance treatment. Journal of substance abuse treatment, 46(1), 43–51. https://doi.org/10.1016/j.jsat.2013.08.012

Seger, C. A. & Spiering, B. J. (2011). A critical review of habit learning and the basal ganglia. Frontiers in systems neuroscience, 5, 66. https://doi.org/10.3389/fnsys.2011.00066

Volkow, N. D., Wang, G. J., & Baler, R. D. (2011). Reward, dopamine and the control of food intake: Implications for obesity. Trends in cognitive sciences, 15(1), 37–46. https://doi.org/10.1016/j.tics.2010.11.001

Wood, W., Mazar, A., & Neal, D. T. (2021). Habits and goals in human behavior: Separate but interacting systems. Perspectives on Psychological Science, 17(2), 590–605. https://doi.org/10.1177/1745691621994226 

Wood, W., Quinn, J., & Kashy, D. (n.d.). Habits in everyday life: Thought, emotion, and action. https://dornsife.usc.edu/assets/sites/545/docs/Wendy_Wood_Research_Articles/Habits/Wood.Quinn.Kashy.2002_Habits_in_everyday_life.pdf 

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