Measuring habit formation through goal-directed response switching

Abstract

<p>Reward-learning theory views habits as stimulus–response links formed through extended reward training. Accordingly, animal research has shown that actions that are initially goal-directed can become habitual after operant overtraining. However, a similar demonstration is absent in human research, which poses a serious problem for translational models of behavior. We propose that response-time (RT) switch cost after operant training can be used as a new, reliable marker for the operation of the habit system in humans. Using a new method, we show that RT switch cost demonstrates the properties that would be expected of a habitual behavior: (1) it increases with overtraining; (2) it increases when rewards are larger, and (3) it increases when time pressure is added to the task, thereby hindering the competing goal-directed system. These results offer a promising new pathway for studying the operation of the habit system in humans.</p>

Habits and Goals in Human Behavior: Separate but Interacting Systems

“…Such a pattern would mirror findings from other paradigms in which inhibition manifests in slower reaction times even when overt responses are correct (e.g., a Stroop task; MacLeod, 1992). In support, a recent set of studies measured both overt responses and reaction time in an outcome-devaluation paradigm (Luque et al, 2020). As in De Houwer et al (2018) and de Wit et al (2018), even participants with strong habits were able to change their overt responses flexibly when outcome values shifted.…”

“…For example, under time pressure, participants expressed habitual responses regardless of whether they were correct, whereas with more time, they were able to prepare and express the correct response to meet current task goals (Hardwick et al, 2019). It is also relevant that extensively learning an instrumental task under time pressure created conflict and delayed responding, suggesting that participants’ habitual responses continued to be activated even when the correct outcomes changed (Luque et al, 2020). Thus, time pressure may encourage not only habit expression at the response stage but also habit formation at the learning stage.…”

“…Thus, lab paradigms would best be structured with extensive repetition to build strong habits, recurring context cues to trigger them, and time pressures and distractions to derail goal pursuit. Also useful are measures, such as reaction time, that can track habit activation despite people’s pursuit of goals (e.g., Luque et al, 2020).…”

Attitudes, Habits, and Behavior Change

“…The strength of cue-response links and the stability of the performance context are paramount. The former is for instance indicated by the speed of responding to habit cues (Neal et al 2012) or the time it takes to switch to a nonhabitized option (Luque et al 2020) or a newly learned response (Hardwick et al 2019).…”

“…This response may be an overt action or habitized thinking (Verplanken et al 2007). While a habit mechanism is not directly observable, it may be inferred from precursors to and consequences of habit formation, for instance habit performance contexts (Wood et al 2005), reaction time measures of context-response associations (Neal et al 2012) or speed of response switching (Luque et al 2020), selfreports of qualities of habitized behavior (Verplanken & Orbell 2003) or habit slips (de Wit et al 2012) (see also Rebar et al 2018). Habitized behavior has qualities such as persistence and insensitivity to new information and alternative choice options (Verplanken et al 1998).…”