Priming effects in the Affect Misattribution Procedure (AMP) have been explained by a misattribution of prime-related affect to neutral targets. However, the measure has been criticized for being susceptible to intentional use of prime-features in judgments of the targets. To isolate the contribution of unintentional processes, the present research expanded on the finding that positive affect can be misattributed to familiarity (i.e., positivity-familiarity effect). To the extent that prime-valence is deemed irrelevant for judgments of target-familiarity, positivity-familiarity effects in the AMP could potentially rule out intentional use of the primes. Seven experiments collectively suggest that prime-valence influences judgments of target-familiarity in the AMP, but only when the task context does not suggest a normatively accurate response to the familiarity-judgment task. Relations of positivity-familiarity effects to self-reported use of prime-valence revealed mixed results regarding the role of intentional processes. Implications for the AMP and misattribution effects are discussed.