Validating neural correlates of familiarity.

Familiarity is a pervasive memory phenomenon that occurs in its most basic form when someone recognizes a repeated stimulus without recollecting other aspects of the requisite prior learning episode. Theoretical controversy currently abounds with respect to both the cognitive and neural characteristics of familiarity. Here, we show that the extant data, particularly brain-potential data, are insufficient for validating putative neural correlates of familiarity, and we outline strategies for making progress on this problem. Conceptual priming is an implicit-memory phenomenon that often occurs together with familiarity; experiments that conflate the two phenomena can be misleading. Avoiding this conflation is required to understand familiarity and to determine the extent to which the neurocognitive processes that support priming also drive familiarity.