Looking Behavior and Relational Memory: Novel Approaches to Analyze Temporal Dynamics of Eye Movements

Patterns of looking behaviors may reveal memory processes. For example, looking preferences toward targets compared to distractors early in a memory retrieval trial have been associated with relational memory processes and its neural substrates. However, current methods do not fully capture visual exploration behaviors that may elucidate how relational processes reinstate memories during retrieval. The goal of this research is to explore whether high temporal-resolution measures of eye-tracking data analyzed as time-series can capture rapid relational memory processes that manifest before behavioral responses. Eye-tracking data were collected during a memory task assessing relational memory for item-space associations in 21 healthy adults (Age: M = 20.93; SD = 1.08). Participants studied a series of items that appeared in one of 32 locations in the middle of the screen along the horizonal line. Participants were later asked to identify the original location of each item among its identical copy, which was presented in a novel location alongside the original item. The distance between identical copies was manipulated (i.e., Close versus Far). Distractor trials included completely novel items presented at two locations. Participants responded by indicating at which location the item was originally shown or whether the item was novel. Cluster-based permutation tests were used to examine time-series of eye-tracking metrics. Results showed that two novel measures, proportional vicinity and exploration-map similarity, reliably discriminated between accurate and inaccurate trials across all experimental conditions. Moreover, both measures showed reliable correlations with hippocampal CA3 subfield volume, consistent with the hypothesis that these indices may capture aspects of pattern separation and completion.