A signal detection theory analysis of behavioral pattern separation paradigms

Behavioral pattern separation (BPS) paradigms ask participants to discriminate previously encoded (old) stimuli from highly similar (lure) and categorically distinct (novel) stimuli. The lure-old discrimination, thought to uniquely reflect pattern separation in the hippocampal formation, is typically pitted against the traditional novel-old discrimination. However, BPS paradigms have measured lure-old discrimination neither consistently across studies nor in such a way that allows for accurate comparison to novel-old discrimination. Therefore, we advocate for signal detection theory (SDT) as a unified framework. Moreover, we compare SDT with previously used measures of lure-old discrimination, indicating how other formulas’ inaccuracies can lead to erroneous conclusions.