Source
Friston, FitzGerald, Rigoli, Schwartenbeck, O’Doherty & Pezzulo (2016), LIT-1476, read in full in NOTE-1138. What its one simulated T-maze task, with hand-set parameters and run once per condition, showed is THEORY-923, which this entry extends.
The claim
The paper states its result as a property of the scheme, not of the one task. In active inference a habit is one more policy, a state-to-state mapping whose transitions and prior grow by counting what the agent does. The paper asserts that such a habit forms from the agent’s observation of its own goal-directed behaviour, and that once acquired it persists after devaluation, while before acquisition behaviour switches at once (NOTE-1138, C1–C2). It goes further and says that, to the extent one accepts the variational formulation, model-free learning cannot be learned apart from model-based behaviour (C7). The authors also concede that at the level of behavioural predictions the scheme probably offers nothing new (p. 876).
What would settle it
The promote_when, which is QUESTION-313: choices of animals or people fitted by this scheme, with the counts estimated from their own history, predicting when behaviour becomes insensitive to devaluation and when it still switches at once. A simulation in another task cannot settle it.