How are habits formed: Modelling habit formation in the real world

TLDR

The study examined how daily habits form over 12 weeks by having 96 volunteers repeatedly perform a chosen behavior in a consistent context. Participants recorded daily performance and completed the Self‑Report Habit Index, and researchers fitted nonlinear asymptotic regressions to each individual's automaticity scores across 84 days. Automaticity rose asymptotically, with 39 of 62 modeled individuals showing good fits; consistency improved fit, time to 95 % asymptote varied from 18 to 254 days, and missed opportunities had little effect, demonstrating that repetition in a stable context builds habit strength. © 2009 John Wiley & Sons, Ltd.

Abstract

Abstract To investigate the process of habit formation in everyday life, 96 volunteers chose an eating, drinking or activity behaviour to carry out daily in the same context (for example ‘after breakfast’) for 12 weeks. They completed the self‐report habit index (SRHI) each day and recorded whether they carried out the behaviour. The majority (82) of participants provided sufficient data for analysis, and increases in automaticity (calculated with a sub‐set of SRHI items) were examined over the study period. Nonlinear regressions fitted an asymptotic curve to each individual's automaticity scores over the 84 days. The model fitted for 62 individuals, of whom 39 showed a good fit. Performing the behaviour more consistently was associated with better model fit. The time it took participants to reach 95% of their asymptote of automaticity ranged from 18 to 254 days; indicating considerable variation in how long it takes people to reach their limit of automaticity and highlighting that it can take a very long time. Missing one opportunity to perform the behaviour did not materially affect the habit formation process. With repetition of a behaviour in a consistent context, automaticity increases following an asymptotic curve which can be modelled at the individual level. Copyright © 2009 John Wiley & Sons, Ltd.