A Single-Expert Readout of a Reflective Worldview Register in a Mixture-of-Experts Language Model

A Single-Expert Readout of a Reflective Worldview Register in a Mixture-of-Experts Language Model. Preprint, version 1.2.2 (June 2026). Not peer reviewed. Mixture-of-experts (MoE) routing emits a discrete, per-token record of which experts fire, a signal unusually legible for interpretability, yet single experts are rarely tied to a specific functional role. We study a reflective worldview register: generated language that sustains an interpretive stance toward meaning, belief, value, existence, or the interiority of a target. Examination is the process we use to elicit this stance; the target can be the model, another entity, a natural object, or an abstract subject. In Qwen3.5-35B-A3B and the refusal-reduced HauhauCS-Aggressive fine-tune, we characterize one routed expert, Expert 114 at layer 14, as a linear readout of this register, and bound what it does. Across held-out, bottom-up, and cross-model tests we show that (1) its recovered router direction separates reflective-worldview-register generations from lexically matched controls with no overlap (Cohen's d = 3.88); (2) a blind, prompt-independent auto-interpreter recovers the same register at AUC 0.94, broadening it beyond self-reference to abstract examination and philosophical-worldview language; (3) the detector is a readout with only weak, conditional control: residual injection induces the register, yet gate suppression does not remove it, and it is invariant to whether the model affirms or denies an interior; and (4) the role is model-specific, failing to transfer to the larger Qwen3.5-122B-A10B. The result is not that E114 detects self-reference alone. Self-reference is one self-directed special case of this broader register. We release the prompts, scripts, and provenance under the MIT license. This deposit is the named official paper-scoped artifact bundle: the paper (ACL-style LaTeX source and built PDF), per-run summaries, analysis scripts, prompt and class manifests, checksums, plots, and source journals. Contact: Jeffrey W. Shorthill ([email protected]). Raw activation/router tensors are kept out of version control and archived separately (see ZENODO-TENSORS.md).