Obsessive-compulsive disorder: Puzzles and prospects

Reflecting on rumination: Consequences, causes, mechanisms and treatment of rumination.

Addiction is driven by excessive goal-directed drug choice under negative affect: translational critique of habit and compulsion theory.

Making Sense of Real-World Scenes.

Habits are commonly conceptualized as learned associations whereby a stimulus triggers an associated response1–3. We propose that habits may be better understood as a process whereby a stimulus triggers only the preparation of a response, without necessarily triggering its initiation. Critically, this would allow a habit to exist without ever being overtly expressed, if the prepared habitual response is replaced by a goal-directed alternative before it can be initiated. Consistent with this hypothesis, we show that limiting the time available for response preparation4,5 can unmask latent habits. Participants practiced a visuomotor association for 4 days, after which the association was remapped. Participants easily learned the new association but habitually expressed the original association when forced to respond rapidly (~300–600 ms). More extensive practice reduced the latency at which habitual responses were prepared, in turn increasing the likelihood of their being expressed. The time-course of habit expression was captured by a computational model in which habitual responses are automatically prepared at short latency but subsequently replaced by goal-directed responses. Our results illustrate robust habit formation in humans and show that practice affects habitual behaviour in two distinct ways: by promoting habit formation and by modulating the likelihood of habit expression. Hardwick et al. show that habits in human behaviour consist of automatic preparation of an action in response to a trigger. Even though we can learn to control habits to perform different action responses, under time pressure, habitual responses resurface.

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Time-dependent competition between goal-directed and habitual response preparation.

Habits are repetitive behaviors that become ingrained with practice, routine, and repetition. The more we repeat an action, the stronger our habits become. Behavioral and clinical neuroscientists have become increasingly interested in this topic because habits may contribute to aspects of maladaptive human behavior, such as compulsive behavior in psychiatry. Numerous studies have demonstrated that habits can be induced in otherwise healthy rats by simply overtraining stimulus-response behaviors. However, despite growing interest in this topic and its application to psychiatry, a similar body of work in humans is absent. Only a single study has been published in humans that shows the effect of extensive training on habit expression. Here, we report five failed attempts to demonstrate that overtraining instrumental behavior leads to the development of inflexible habits in humans, using variants of four previously published outcome devaluation paradigms. Extensive training did not lead to greater habits in two versions of an avoidance learning task, in an appetitive slips-of-action task, or in two independent attempts to replicate the original demonstration. The finding that these outcome devaluation procedures may be insensitive to duration of stimulus-response training in humans has implications for prior work in psychiatric populations. Specifically, it converges with the suggestion that the failures in outcome devaluation in compulsive individuals reflect dysfunction in goal-directed control, rather than overactive habit learning. We discuss why habits are difficult to experimentally induce in healthy humans, and the implications of this for future research in healthy and disordered populations. (PsycINFO Database Record

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Sarah L. Knot

Papers

Shifting the balance between goals and habits: Five failures in experimental habit induction.

Conflict in the kitchen: Contextual modulation of responsiveness to affordances