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キーワード:
Obesity; BMI; Impulsivity; Sensation seeking; Habitual; Goal-directed; Instrumental discrimination
要旨:
According to dual-system theory, instrumental learning and performance depend on the balance between goal-directed and habitual
action control. Overreliance on habits has been argued to characterize clinical conditions such as drug addiction or obsessivecompulsive
disorder as well as obesity and excessive impulsivity. A tendency towards habitual action control in obesity has already
been indicated in the food domain. However, impairments might not be restricted to eating behavior. This has been suggested by
domain-general obesity-associated disturbances in executive function as well as alterations in corticostriatal circuits underlying
the goal-directed and habitual systems. In this study we examined the balance of goal-directed and habitual action control in a
sample of normal-weight, overweight, and obese participants (n=105) using the slips-of-action test in a non-food context. We
tested for continuous or group-based associations between body weight status (BMI) and the devaluation sensitivity index (DSI), a
parameter representing the balance of the goal-directed and habitual systems in action control. As personality differences in the
domain of impulsivity might affect this relationship, we also examined whether the interaction between BMI and self-reported
impulsivity, based on the UPPS Impulsive Behavior Scale, was related to the DSI. In addition to that, we tested for direct, i.e.,
weight status independent, relationships between UPPS subdomains of impulsivity and the DSI. We failed to find evidence for a
relationship between weight status and sensitivity to devaluation as indexed by the DSI. However, independent of weight status,
we observed lower sensitivity to devaluation in sensation seekers, a subtype of impulsivity. To conclude, behavioral flexibility in
the sense of disturbances in the balance between the habitual and goal-directed systems seems to be unaffected by weight status
in a non-food context. Consequently, stimuli and behavior might not be generally excessively linked in overweight or obesity.
However, according to ceiling effects we cannot rule out subtle effects the paradigm was not able to disentangle. Further, future
studies are needed to clarify the role of specific subtypes of obesity (e.g., food addiction). The indicated habit propensity in
sensation seekers may account for previous reports of weak avoidance behavior and risky decision making.
