Subjective confidence in perceptual judgments: a test of the self-consistency model

Two questions about subjective confidence in perceptual judgments are examined: the bases for these judgments and the reasons for their accuracy. Confidence in perceptual judgments has been claimed to rest on qualitatively different processes than confidence in memory tasks. However, predictions from a self-consistency model (SCM), which had been confirmed for general-information questions (Koriat, 2010) and social attitudes (Koriat & Adiv, 2010), are shown to hold true also for perceptual judgments. In SCM, confidence is modeled by the procedure for assessment of statistical level of confidence: For a 2-alternative, forced-choice item, confidence is based on the consistency with which the choice is favored across a sample of representations of the item, and acts as a monitor of the likelihood that a new sample will yield the same choice. Assuming that these representations are drawn from commonly shared populations of representations associated with each item, predictions regarding the basis of confidence were confirmed by results concerning the functions relating confidence and choice latency to interparticipant consensus and to intraparticipant consistency for majority and minority choices. With regard to the confidence-accuracy (C/A) relationship, the consensuality principle, documented for general-knowledge tasks (Koriat, 2008a), was replicated for perceptual judgments: Confidence correlated with the consensuality of the choice rather than with its correctness, suggesting that the C/A correlation is due to the relationship between confidence and self-consistency and is positive only as long as the correct choices are the consistently made choices. SCM provides a general model for the basis and accuracy of confidence judgments across different domains.