Polyvagal theory
Stephen Porges’s account of autonomic organization, entering the wiki as scaffolding for Somatic Experiencing in Payne et al. (2015) rather than as a primary source. What follows is the theory as SE deploys it; the wiki has not yet read Porges first-hand (his 2004 and 2007 papers are not in raw/), so the claims below inherit whatever is right or wrong in the original.
The three divisions
Where the classical picture has two reciprocal autonomic branches (sympathetic ↔ parasympathetic), Porges splits the parasympathetic in two along evolutionary lines:
| division | evolutionary age | function | behavioural signature |
|---|---|---|---|
| Sympathetic | — | mobilization for threat | fight/flight, arousal |
| Dorsal vagal (parasympathetic) | older | shutdown, immobilization | freeze, collapse, dissociation, feigned death |
| Ventral vagal (parasympathetic) | newer (mammalian) | social engagement | eye contact, vocal prosody, facial expression, hearing, feeding |
The ventral-vagal “social engagement system” is the theory’s distinctive element: it recruits the supradiaphragmatic vagus and the cranial nerves of the face and voice, and is proposed as a nuanced brake on sympathetic activation that works through social connection rather than through simple parasympathetic rebound.
How SE uses it
Two SE moves rest on the theory:
- Social engagement as regulation. The therapist’s eye contact, warm voice, and calm presence are read as recruiting the client’s ventral-vagal system to downregulate sympathetic arousal — the physiological rationale for “resourcing” and for the relational safety SE builds before touching trauma. See payne-2015-somatic-experiencing.
- The freeze/dissociation state as dorsal-vagal. SE identifies the freeze, collapse and dissociation of severe trauma with dorsal-vagal shutdown co-activating with sympathetic mobilization — its account of tonic-immobility and of why some traumatized clients present numbed and shut-down rather than hyperaroused.
Neuroception (Porges 2004) also enters here: a subcortical, pre-cortical detection of threat vs safety, which SE aligns with the core-response-network’s claim to respond to threat “with little input from higher cortical evaluative processes.”
Where it touches the wiki’s existing concerns
The theory makes an implicit autonomic-specificity claim — that distinct autonomic states (mobilize / shut down / socially engage) are physiologically separable — which connects it to the wiki’s long-running debate over whether emotional states have distinct autonomic signatures. But polyvagal theory is contested in the wider literature (its comparative-anatomy and cardiac claims have drawn sustained criticism), and the wiki holds no critical source on it yet. Filed provisionally: a widely-used trauma-therapy framework, load-bearing for SE’s relational and freeze-state claims, held here only as SE reports it and flagged for first-hand reading when a Porges paper reaches the queue.