Hierarchical searching in episodic memory

TL;DR

This paper investigates hierarchical search mechanisms in episodic memory through analysis of free-recall data and a simple random-walk model, revealing non-monotonic recall patterns suggestive of hierarchical search processes.

Contribution

It introduces the hypothesis of hierarchical search in memory and tests it using empirical data and a binary-string random-walk model, providing new insights into recall dynamics.

Findings

Identified non-monotonic patterns in free recall data.

Supported the hierarchical search hypothesis with model simulations.

Highlighted potential mechanisms underlying recall anomalies.

Abstract

An analysis of free-recall datasets from two independent experiments allows to identify two anomalous instances of non-monotonicity in free recall: a maximum in the dependence of the inter-response intervals on the serial-position lags, and a minimum in the rate of contiguous recall near the beginning of the recall process. Both effects, it is argued, may stem from a hierarchical search protocol in the space of memories. An elementary random-walk model on binary strings is used to test this hypothesis.