Casper Hesp, Ryan Smith, Thomas Parr, Micah Allen, Karl J. Friston & Maxwell J. D. Ramstead (2021), Neural Computation 33(2):398–446 — DOI-10.1162/neco_a_01341
Key takeaways
- Valence is inferred from confidence in one’s action model. “agents infer their valence state based on the expected precision of their action model—an internal estimate of overall model fitness (“subjective fitness”)” (p. 399).
- Affective charge (AC) is the update to that precision. It “lends a sign to otherwise unsigned divergences between predictions and outcomes” (p. 399). It is zero when policies go as expected and positive or negative as outcomes raise or lower confidence (pp. 409–410).
- What γ does. “higher γ values afford a greater influence of the expected free energies of each policy entailed by one’s current action model” (p. 408), against a fixed habitual prior over policies. With low γ the agent will “fall back on her baseline prior over policies” (p. 420).
- The deep level. A second level, slower and across trials, holds a binary valence state. It takes AC as evidence and sets the lower level’s prior on γ (pp. 416–420). The authors stress that they “do not equate this notion of expected precision (or confidence) with valence directly” (p. 426).
- “Felt” means explicitly represented. “Presumably this type of explicit valence representation is also a necessary condition for self-reportable experience of valence” (p. 429). And “it is an open question which level or subset of levels may be privileged with respect to its contribution to affective phenomenology” (p. 433).
- A simulation, not data. A T-maze over 64 trials with reversal at trial 33. The valence level speeds re-adaptation and attenuates repeated AC. Before reversal, “their behaviors were indistinguishable” (p. 425).
- Its own hardest problem. It names “the strongest and most important challenge” (p. 430): dopamine, a candidate carrier of AC, is tied to “wanting” rather than pleasure.
Standing in the record
Filed on 2026-10-23 for the record’s candidate that a valence regime is felt when the system models its own potential (CLAIM-440), after Brouillet and Friston (NOTE-785, THEORY-662), who cite this paper for valence. Structurally, it is the nearest existing model of that candidate. γ is the weight of one ordering against another in policy selection, and the deep level models it. But it identifies valence with the self-model, not with the potential. And it makes negative valence a weakening of the preference ordering’s potential. Read in NOTE-1111.