An Ability Label Raises the Effort of an Agent

Abstract

An ability label is a sentence that tells a worker how it is expected to perform before the work begins. In humans such labels move outcomes: a positive expectation raises performance (the Pygmalion effect) and a salient negative stereotype lowers it (stereotype threat). Whether a language-model agent responds to the same sentence, and in which direction, is an open question the human designs cannot answer, because they cannot hold ability constant across labeled groups. A model can: same weights, same task, same seeds, only the label differs. This five-stage, pre-registered study of one agentic task with a held-out grading criterion found no effect of group-form labels for Opus 5 or GPT-5.6 Sol at 20 seeds per cell. An individual-form negative label raised the reasoning tokens Opus 5 spent by about half a standard deviation (p = 0.0106 over 30 matched seeds): the negative label raised effort rather than depressing it, the opposite of the human prediction.

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