Brain Injury Rewires Risk Calculation, Makes People Gamble Against Their Interests
Damage to the frontal lobe fundamentally changes how people weigh financial risks, causing them to accept bad bets they'd normally reject. The finding could reshape clinical assessments of decision-making capacity after head injury and inform workplace safety protocols for at-risk populations.
Originaltitel: Frontal brain injury alters human risky choices in self and other contexts
Frontal hjärneskador förändrar hur patienter väger risk — en upptäckt som får betydelse för bedömning av arbetsförtjänad och försäkringsmedicin. Forskare jämförde tjugo patienter med frontala skador med tjugo friska kontroller genom att låta dem acceptera eller avslå osäkra vadslagningar för sig själva eller en anonym person. Patienterna accepterade mer ogynnsamma spel för egen räkning men var försiktigare när det gällde andra. Beräkningsmodeller visade att förlustaversion minskade mest hos patienterna — de värderade negativa utfall lägre än normalt. Skadorna omfattade främst ventromedial prefrontal cortex. Fyndet förklarar varför frontala skador orsakar paradoxal riskbeteende: patienter tar större personlig risk medan de samtidigt är överprotektiva för andra. För inköps- och försäkringsbeslut i vården blir detta relevant vid neuropsykiatrisk screening av beslutsfattare.
Frontal lobe integrity is crucial for risky decision-making. We investigated how frontal lesions affect computational mechanisms underlying risk when decisions impact oneself versus others. Twenty patients with frontal damage and 20 matched controls accepted or rejected mixed-outcome gambles for themselves or an anonymous other. Patients accepted more disadvantageous gambles than controls in the self condition and showed greater caution for another person; controls showed no self-other difference. Formal model comparison favored a four-parameter Prospect Theory model. Relative to controls, patients showed near-linear probability weighting, reduced loss aversion, and steeper utility curvature; counterfactual analysis identified reduced loss aversion as the principal driver of increased acceptance of disadvantageous gambles. Parameter differences were consistent across conditions; the behavioral dissociation was not reflected computationally. Lesion overlap revealed heterogeneous frontal damage with common ventral and medial prefrontal involvement. These findings provide a mechanistic account of how frontal damage produces dissociable decision patterns across social contexts.