Heart of Glass: Listening for a Fragile Affective Pulse in Language Models

The same event can frighten one person and thrill another. Appraisal, constructionist, and cultural theories of emotion locate that difference in how the event is read against goals, relationships, and learned meanings. Critics of emotion-like directions in language models have set out what it would take to say a model has emotions: context-dependent appraisal, first-person structure, attention control, persistence, and action on its own behalf. One critic orders these from thin to thick functional roles. We reproduce and extend the community’s published directions to test which of these criteria they meet, and ask whether they are the right criteria. Our central design holds an event fixed and varies only how it is read, tested across 650 events with contrasting appraisals and several open-weight models. The evaluative directions we find look like stained glass: same-named directions built by different recipes barely overlap, and each faces its own way. Against random directions, a published self-facing pain direction rarely stands out, and a grammar-controlled harm component tracks how the target is named without being shown to single out the model. Steering an appraisal shifts the emotion a model names and the explanation it gives, and the reading travels largely through those words, with carried internal state adding to it. Emotional content makes a model turn to the user before answering a buried question, by way of a state set at the start of its turn. In two of four models steering along fear turns that delay into misses. Some of the clearest function lies outside these criteria: a state that anticipates when a model will change course (in the two small models only; Gemma 4 31B showed none), and a better/worse direction that tracks what a model says about how a session feels. Pushed hard, combined directions make replies warmer and less faithful to the event. Several of the thickest criteria picture emotion as a lasting state inside one agent, while constructionist and cultural accounts treat it as constructed in the moment and between people. The criteria our models fail are largely the agent-centered ones. What emerges is a heart of glass: clear enough to read, responsive to specific dials, and liable to crack, into warmer but less faithful accounts or outright collapse, along lines that differ from model to model.