Similar time course of fast familiarity and slow recollection processes for recognition memory in humans and macaques

Abstract

According to dual-process theory, recognition memory performance draws upon two processes, familiarity and recollection. The relative contribution to recognition memory are commonly distinguished in humans by analyzing receiver-operating-characteristics (ROC) curves; analogous methods are more complex and very rare in animals but fast familiarity and slow recollective-like processes (FF/SR) have been detected in non-human primates (NHPs) based on analyzing recognition error response time profiles. The relative utility of these methods to investigate familiarity and recollection/recollection-like processes across species is uncertain; indeed, even how comparable the FF/SR measures are across humans and NHPs remains unclear. Therefore in this study a broadly similar recognition memory task was exploited in both humans and NHPs to investigate the time course of the two recognition processes. We first show that the FF/SR dissociation exists in this task in human participants and then we demonstrate a similar profile in NHPs which suggests that FF/SR processes are comparable across species. We then verified, using ROC-derived indices for each timebin in the FF/SR profile, that the ROC and FF/DR measures are related. Hence we argue that the FF/SR approach, procedurally easier in animals, can be used as a decent proxy to investigate these two recognition processes in future animal studies, important given that scant data exists as to the neural basis underlying recollection yet many of the most informative techniques primarily exist in animal models.