Abstract
When targets appear in a detection task, unrelated but concurrent stimuli will gain a boost in relational memory, the ability to remember the spatial and temporal relationship between items (Turker & Swallow, 2019). This may reflect enhanced perceptual and relational processing of events by temporal selection, resulting in better representations improving subsequent retrieval. However, alternative or additional factors can exist, from improved memory search to simple response bias. We therefore estimated evidence accumulation, response bias, decision threshold, and non-decision time by fitting drift diffusion models (Ratcliff & McKoon, 2008) to response time data on recognition tasks. In five experiments, three previously reported in Turker & Swallow (2019), participants encoded visual scenes while performing a simultaneous detection task on an unrelated stream of target and distractor cues (male and female faces) appearing over the left or right half of the scene. Some participants were asked to also encode face identity (intentional face encoding), while others were not (incidental face encoding). Participants were later asked to indicate which of two scenes had been presented during encoding and to report the identity and the location of the face that was paired with the scene. Across experiments and conditions, evidence accumulation was higher for the background scenes, face identity, and face location when the face was the target gender than when it was the distractor gender. Response bias did not significantly differ across target and distractor conditions. Although evidence accumulation could reflect either improved memory search or enhanced encoding of the images, an fMRI study with a similar paradigm (Moyal et al., preprint), revealed increases in BOLD activity and better classification of stimuli under target conditions during encoding in visual cortex. Thus, combined with our drift diffusion modeling, our results suggest that temporal selection of behaviorally relevant moments enhances perceptual and relational processing.