Dr. Ali Ghazizadeh, Associate Professor of Electrical Engineering at Sharif University of Technology, along with his research team and in collaboration with the Institute for Research in Fundamental Sciences (IPM), has published a significant study in Nature Communications.
Titled “Why Old Habits Return Even After Apparent Success in Changing Them,” the research reveals that the brain uses two reinforcement learning systems with different time scales. One is slow and stable, preserving long-standing habits; the other is fast and flexible, enabling rapid adaptation to new conditions—but its influence fades over time. As the flexible system weakens, behavior reverts to the stable system, explaining why ingrained behaviors—such as those seen in addiction or relapse—are so hard to permanently change.
Notably, the team identified the prefrontal cortex as the brain region where these two systems simultaneously encode and compete, balancing stability and adaptability.
Nature Communications, launched in 2010, is a leading open-access journal under the Nature umbrella, covering natural sciences including biology, physics, chemistry, and earth sciences. It holds a five-year impact factor of 17.2, an H-index of 577, and an SJR score of 4.761, ranking it in the Q1 category for Biochemistry, Genetics, and Molecular Biology.
This theoretical framework offers new insights into habit formation and relapse, and could inform more effective strategies for behavioral change and retraining.