Naked Neuroscience, from the Naked Scientists · James Tytko

Extremist brains, and expelling traumatic memories

·25 min

This episode of Naked Neuroscience, hosted by James Titko, explores the neuroscience behind political extremism, the genetic influence of peer groups, and an experimental sleep therapy for PTSD. Political neuroscientist Lios Migrod discusses her research into extremist brains, while sociogenomics researcher Jessica Salvatore presents findings on peer influence, and psychiatrist Hein van Marle explains a novel sleep-based treatment augmentation. Migrod's work identifies cognitive rigidity, or inflexible information processing, as a key trait predicting extremist views across the ideological spectrum. Her research also links emotional dysregulation, impulsivity, and thrill-seeking to a greater willingness to endorse ideological violence. Studies of convicted ideologically-driven criminals in the US found a common history of personal isolation, rejection, or financial trouble preceding their actions. Migrod notes social media algorithms circulate emotionally dysregulating content, which can disproportionately impact psychologically vulnerable individuals. Her research aims to understand psychological resilience to misinformation and dogmatic thinking. Jessica Salvatore's study used Swedish national data to map the genetic risk of adolescents' peers based on family histories of psychiatric disorders. The research found a peer's genetic predisposition increased an individual's later risk of developing alcohol use disorder, drug use disorder, major depression, or anxiety. These "peer social genetic effects" remained significant even after controlling for the peers' own behavioral outcomes and family socioeconomic factors. The effects were stronger for externalizing disorders like substance abuse than for internalizing disorders like depression and anxiety. A surprising insight is that psychological factors like personal alienation can be stronger predictors of extremist action than demographic factors like age or education. Migrod emphasizes that cognitive traits like rigidity are not fixed and can be changed through societal efforts to foster flexibility. Salvatore's work flips the nature-nurture debate by proposing our social environments themselves have a "genotype" that influences our health. The experimental PTSD treatment uses Targeted Memory Reactivation (TMR), playing auditory clicks during sleep to reinforce therapy conducted while awake. Researcher Hein van Marle confirmed the procedure was safe and did not trigger extra nightmares or symptoms in patients. The study found the TMR cues successfully enhanced specific brainwave activity linked to memory consolidation during sleep. The tone is educational and conversational, blending interview segments with clear scientific explanations from the host. The style is structured, moving crisply between three distinct research stories with clinical and social implications. Listeners interested in the psychological roots of political violence and the intersection of genetics and social environment will find this episode compelling. Those seeking definitive solutions or conclusive clinical trial results might find the nuanced, ongoing nature of this research less satisfying.

As heard by us

A clear, fast-moving look at political extremism, peer effects, and PTSD treatment in neuroscience.

Political extremism, peer influence, and PTSD treatment sit at the center of this episode, and the result is a clear reminder that the brain is shaped by social and biological forces, not sealed off from them.

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Why you'd press play

When extremism, peer influence, and PTSD all sit on the same brain map.

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