Episodic-like memory in a gorilla: A review and new findings

The current paper examines if gorillas (Gorilla gorilla gorilla) possess an episodic memory system. Episodic memory, in humans, is a neurocognitive system that stores information about the personal past. Unique to episodic memory is its palinscopic or past-focused orientation; most memory systems serve to provide the organism with up to date knowledge of the current state of the world. We review four operational definitions that have been used to address issues of episodic memory in non-humans and review the literature with a focus on the studies previously done on gorillas. We describe two new studies with King, an adult male western lowland gorilla. We show that King can remember the order of past events (Experiment 1) and that King can remember where events occurred (Experiment 2). We conclude by discussing alternate explanations of our findings and speculate on future directions. (c) 2005 Elsevier Inc. All rights reserved.