Anthropic just released a new post on emergent introspective awareness in LLMs.
Here are my notes:
The key experiment: the team injected concept vectors—anger, justice, etc. directly into the model’s hidden activations, then asked, “Do you feel anything unusual in your thoughts?”
Roughly 20 % of the time, Claude 4.1 detected the injection and named the concept before it could be inferred from its own output—an instance of the model reading its own activations.
Introspective awareness is defined by four strict criteria:
- Accuracy: the self-report must be true
- Grounding: the report must causally depend on the internal state
- Internality: awareness must arise from within, not from observing external outputs
- Metacognition: it must be a thought about a thought
Further tests show Claude can:
- Distinguish injected thoughts from input text
- Tell whether a response was genuinely its own or prefilled by the user
- Even modulate its internal activations when instructed to think—or not think—about a concept
Anthropic calls this functional introspection: not consciousness, but a measurable, causal form of self-access.