Determining the effects of training duration on the behavioral expression of habitual control in humans: a multilaboratory investigation
It has been suggested that there are two distinct and parallel mechanisms for controlling instrumental behavior in mammals: goal-directed actions and habits. To gain an understanding of how these two systems interact to control behavior, it is essential to characterize the mechanisms by which the balance between these systems is influenced by experience. Studies in rodents have shown that the amount of training governs the relative expression of these two systems: Behavior is goal-directed following moderate training, but the more extensively an instrumental action is trained, the more it becomes habitual. It is less clear whether humans exhibit similar training effects on the expression of goal-directed and habitual behavior, as human studies have reported contradictory findings. To tackle these contradictory findings, we formed a consortium, where four laboratories undertook a preregistered experimental induction of habits by manipulating the amount of training. There was no statistical evidence for a main effect of the amount of training on the formation and expression of habits. However, exploratory analyses suggest a moderating effect of the affective component of stress on the impact of training over habit expression. Participants who were lower in affective stress appeared to be initially goal-directed, but became habitual with increased training, whereas participants who were high in affective stress were already habitual even after moderate training, thereby manifesting insensitivity to overtraining effects. Our findings highlight the importance of the role of moderating variables such as individual differences in stress and anxiety when studying the experimental induction of habits in humans.
Additional Information© 2022 Pool et al.; Published by Cold Spring Harbor Laboratory Press. This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first 12 months after the full-issue publication date (see http://learnmem.cshlp.org/site/misc/terms.xhtml). After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/. Received March 19, 2021; accepted in revised form October 29, 2021. This work was supported by an Early Postdoctoral Mobility fellowship from the Swiss National Science Foundation (P2GEP1162079) to E.R.P. and by a grant from the National Health and Medical Research Council of Australia to B.B. (GNT1079561). L.S. received funding from the Landesforschungsförderung Hamburg (FV38). T.S. is supported by funding from the Israeli Science Foundation 2004/15. G.N is supported by funding from a National Science Foundation Early Career Development Program grant (no. 1942917), and thanks Carlos and Rosa de la Cruz for ongoing support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Dr. Ben Meuleman and Dr. Yoann Stussi for their thoughtful advice on statistical analysis, and Dr. Vanessa Sennwald for her insightful comments on the manuscript. Data Deposition. Data from the study and code for the experimental task and the statistical analysis are available through the GitHub repository: https://github.com/evapool/MULTILAB_HABIT.
Published - Learn._Mem.-2022-Pool-16-28.pdf
Submitted - 10.31234osf.ioz756h_.pdf
Supplemental Material - Supplemental_Materials.pdf
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