Interoception & Affect outline
Bodily signals---heart rate, breath, visceral sensations---set affective tone and salience; prediction errors about body state generate emotion, shaping what gets attention and which actions run.
Perception isn't just about the external world---it's also about the body. Interoception tracks visceral signals: heart rate, breath, gut sensations, muscle tension, temperature. These signals aren't decorative; they set affective tone and salience, shaping what the brain attends to and which actions it selects. When your body signals "something's off"---a faster heartbeat, a tightness in the chest, a pit in the stomach---that's not separate from cognition. It's the substrate of emotion, and emotion is what tells you whether to act and how.
The predictive processing architecture extends to the body: the brain generates predictions about what your heart rate, breathing, and visceral state should be, and when those predictions fail---when bodily state violates expectations---you feel it as affect. George Mandler called this the interruption theory of emotion: automatic routines run smoothly until something interrupts them, and that interruption is the emotion. The bodily prediction error doesn't just signal "something's wrong"; it colours how you interpret the external world and biases which neural pathways get activated.
There's no action without emotion because there's no reason to do anything unless it has affective significance---unless it feels good, bad, urgent, interesting, safe, threatening. Even "rational" decisions are grounded in bodily evaluations of what matters. The peripheral nervous system constantly informs the central nervous system about the state of the body, and that information is the precursor to every decision you make. If you suspect you're being "too emotional" and decide to do something else, that "something else" is still motivated by a bodily sense that it's better---perhaps referencing an imagined future bodily state that feels more favourable than the present one.
This architecture also explains why state management matters so much for behaviour change. Bodily arousal tunes the system: high arousal (signalled by neuromodulators like norepinephrine and cortisol) tightens predictions and narrows attention---you fall back on familiar routes. Low arousal broadens the aperture---you're more exploratory, more willing to update. If you want a new behaviour to be available under stress, you have to practise it while stressed, because stress is a bodily context, and retrieval depends on matching encoding context. Regulate the body, and you regulate what the system predicts, attends to, and does.
How can you think with this?
These heuristics help you apply this neural system:
Ways to think with this
Practical ways to use this neural mechanism in understanding behaviour
WIP: Bodily signals set the agenda
Interoception tracks visceral state---heart rate, breath, gut sensations, muscle tension---and these signals aren't separate from cognition. They set affective tone and salience, shaping what the brain attends to and which actions it selects. Prediction errors about bodily state generate emotion, and emotion is what tells you whether to act and how. There's no action without affect because there's no reason to do anything unless it has bodily significance.
So what can you do? Recognise that even 'rational' decisions are grounded in bodily evaluations. If you're trying to override an impulse by reasoning it away, you're still acting on a bodily sense that the alternative is better---perhaps referencing an imagined future bodily state. The move isn't to suppress emotion; it's to regulate the bodily state so the system generates predictions aligned with your goals.
WIP: State is context
Bodily arousal tunes the system: high arousal tightens predictions and narrows attention; low arousal broadens the aperture. This means arousal is a form of context, and context dependence applies. If you want a new behaviour to be available under stress, you have to practise it while stressed, because stress is a bodily context and retrieval depends on matching encoding context.
So what can you do? Train behaviours under the bodily states where you'll need them. If the behaviour is meant for calm conditions, practise it calm. If it's meant for high-stakes moments, gradually introduce arousal during practice so the pathway consolidates in that state. And if you're trying to change stress responses, regulate the body first---calm breathing, grounding, physical movement---so the system is in a state where updating is possible.
WIP: Interrupt theory explains urgency
George Mandler's interruption theory of emotion says that automatic routines run smoothly until something interrupts them, and that interruption is the emotion. Bodily prediction errors don't just signal 'something's off'---they colour how you interpret the external world and bias which pathways get activated. A faster heartbeat or a pit in the stomach isn't decoration; it's the substrate of urgency, fear, or excitement, and it shapes what you do next.
So what can you do? Notice bodily signals as information, not commands. An elevated heart rate tells you the system is flagging something as salient, but it doesn't tell you what to do about it. You can use that arousal to sharpen focus and execute quickly, or you can pause and check whether the bodily signal is accurate---whether the predicted threat is real or a false alarm left over from an old pattern.
Sources
- neurotypica/content/archive/anatomy-emotions.md
- neurotypica/content/archive/anatomy-nervous-system.md
- articles/interruption-theory-of-emotion-mandler.md
- analects/predicting-human-behaviour.md