Huang & Bargh (H&B) propose an interesting theory of unconscious motivation, based in part on evolutionary principles. Early clinical notions of unconscious processes highlighted their importance in compulsive and impulsive disorders, and the target article does refer on occasion to such conditions (e.g., drug addiction). It may, however, be useful to pay additional emphasis to such psychopathology, with particular reference to the question of whether H&B's arguments are valuable in explaining not only normal, but also abnormal motivational processes.

The inconsistency principle, for example, seems particularly apparent in individuals with compulsive and impulsive disorders, such as obsessive-compulsive disorder (OCD) and addiction. Early on Freud emphasized the important contrast between obsessional and hysterical neurosis. More recent work continues to describe how individuals with OCD engage in repetitive behaviour despite acknowledging the absurdity of such compulsions (Foa et al. Reference Foa, Kozak, Goodman, Hollander, Jenike and Rasmussen1995); similarly, individuals with addiction are unable to cease drug consumption despite being aware that this is not in their bests interests (Loewenstein Reference Loewenstein1996).

There is growing evidence that an unconscious habit system may play a crucial role in explaining the inconsistency seen in both OCD and drug addiction. OCD may be characterized by an underlying vulnerability to habit formation (Gillan et al. Reference Gillan, Morein-Zamir, Urcelay, Sule, Voon, Apergis-Schoute, Fineberg, Sahakian and Robbins2013). Although drug addiction may be precipitated by an underlying vulnerability to impulsivity, the addiction process is stimulus-driven and characterized by repetitive, inflexible, and persistent behaviour despite associated negative consequences (Everitt & Robbins Reference Everitt and Robbins2005; Volkow & Fowler Reference Volkow and Fowler2000). Put differently, habits restrict agency by prompting automatic responses to environmental cues (e.g., a dirty toilet in OCD, an inviting pub in alcoholism), regardless of whether or not the outcome is detrimental to the individual (Dickinson Reference Dickinson1985). Crucially, habits may be a driving mechanism in both avoidant (e.g., OCD) and appetitive (e.g., drug addiction) motivational processes (Gillan et al. Reference Gillan, Morein-Zamir, Urcelay, Sule, Voon, Apergis-Schoute, Fineberg, Sahakian and Robbins2013). Typically, behavioural control is maintained through a balance between the goal-directed system and the habitual system (Dickinson Reference Dickinson1985; de Wit & Dickinson Reference de Wit and Dickinson2009). The appropriation of control away from the goal-directed system toward the habitual system in OCD and drug addiction may be underpinned by anomalies in the frontostriatal circuits governing these functions (Balleine & O'Doherty Reference Balleine and O'Doherty2010; de Wit et al. Reference de Wit, Watson, Harsay, Cohen, van de Vijver and Ridderinkhof2012).

Although habitual behaviour in drug addiction and OCD seems to be defined by a relative lack of goal-directedness, H&B's theory of the “selfish” nature of goals may well have some application to abnormal motivational processes in these disorders. Specifically, one may consider habits characterizing OCD and drug addiction to be “selfish,” insofar as they involve adaptive systems. Thus, several authors have emphasized that precautionary behaviours and reward-seeking behaviours have an evolutionary basis (Nesse & Berridge Reference Nesse and Berridge1997).

We suggest that H&B's theory provides some useful insights into understanding compulsive and impulsive disorders insofar as it emphasizes continuity between unconscious and conscious motivational processes, in addition to the notion of the “selfish” or adaptive nature of habitual processes. However, we would argue that additional work is needed in order to address the neurocircuitry and neurochemistry that characterize the relevant motivational processes; there is a good deal of relevant literature (e.g., Everitt & Robbins Reference Everitt and Robbins2005; Graybiel & Rauch Reference Graybiel and Rauch2000) that may contribute to delineating the precise way in which such processes operate, and which may be of specific value in the treatment of psychopathology.