The Long Argument About Habit

Habit is one of the oldest words in the discipline and one of the least stable. It arrived in nineteenth-century writing as a general principle of nervous plasticity, was narrowed by behaviourism into a learned association between a situation and a response, was largely set aside when the field turned to information processing, and returned late in the twentieth century in a more specific form.

The behaviourist definition and its cost

Under the behaviourist account, a habit was a strengthened link between a stimulus and a response, built by repetition and reinforcement. The definition had the virtue of being measurable and the defect of leaving no room for what the actor expected the action to achieve. Since a great deal of behaviour plainly is governed by expected outcomes, the account looked less like a theory of action than a theory of one special case.

Two systems rather than one

The version that took hold later treats those as two different modes rather than rivals. In goal-directed mode, behaviour tracks the current value of the outcome: if the outcome stops being worth having, the behaviour stops. In habitual mode, behaviour is triggered by the situation and persists for a while even after the outcome loses its value. The distinguishing test is therefore not how automatic something feels but whether it survives a change in what the outcome is worth.

That test is the useful part of the framework, and it is the part most often dropped when the idea is summarised outside the field. Once habit is defined by the feeling of automaticity alone, almost anything qualifies and the term stops doing work.

Formation and the number in circulation

The popular question is how long a habit takes to form, usually accompanied by a specific figure. The research that gets cited for such figures generally reports wide variation between people and between behaviours, with simple actions in stable settings shifting far faster than complex ones. Reporting the centre of a wide distribution as though it were a constant is a summarising error rather than a finding.

Context as the underrated variable

The most consistent theme across the modern literature is the weight of stable context. Behaviour that recurs in one setting becomes bound to that setting, and it is disrupted when the setting changes, which is why moving house or changing a route interrupts patterns that felt fixed. Habit, on this reading, is at least as much a property of the arrangement of a life as of the person living it.

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