A Test of Bias Towards Prototypical Features in Monkey Memory Open Access

Abstract

It is widely accepted that humans have evolved multiple memory systems to address different cognitive and behavioral demands. One such system is working memory, a form of short-term memory that temporarily holds information in readily accessible form, allowing us to perform tasks like reasoning, comprehension, and learning. Despite the vital importance of this type of memory it is limited to about 3-5 items. Humans overcome these limitations through the integration of working memory representations and prototypical knowledge. That is, when recalling well known items from working memory, we use prototypical knowledge to fill in missing information. The human literature demonstrates that this creates memory errors biased towards prototypes, yet it is not clear whether this is a uniquely human phenomenon, an evolved characteristic, or a fundamental property of memory. Studying non-human animals helps us understand this bias by providing insight into its evolutionary history. This study investigated this interaction and its evolutionary history in rhesus macaques because their extensive role in research has demonstrated that they have working memory and form prototypes. Specifically, we showed a monkey shape-specific features thousands of times, to incorporate the feature into a prototypical representation of the shape. We then had the feature vary from the prototypical value and tested the monkey’s memory for the feature using the match to sample paradigm. Overall, we did not observe a significant bias towards the prototypical feature. Potential explanations for these findings and ways future research can improve on conceptual and methodological limitations are discussed below.

Table of Contents

A Test of Bias Towards Prototypical Features in Monkey Memory 1

Method 5

Subjects & Testing Environment 5

Experiment 1 Stimuli 5

Colors 6

Pattern-Sizes 7

Experiment 2 Stimuli 7

Procedure 8

Color-Match Training 8

Size-Match Training 9

Task Integration 10

Experiment 1 Testing: Short Delay 11

Experiment 1 Testing: Long Delay 12

Experiment 2 Testing 12

Statistical Analyses 12

Results & Discussion 13

Experiment 1 Results 13

Experiment 1 Discussion 15 

Experiment 2 Results 16

Experiment 2 Discussion 17

General Discussion 18

References 21

About this Honors Thesis

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School	Emory College
Department	Psychology
Subfield / Discipline	Neuroscience and Animal Behavior
Degree	B.A.
Submission	Honors Thesis
Language	English
Research Field	Psychology, Cognitive
Keyword	monkeys working memory evolution semantic memory prototype effect
Committee Chair / Thesis Advisor	Robert R. Hampton, Emory University
Committee Members	Benjamin Wilson, Emory University Jane Foley, Emory University

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Supplemental Files

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	Training Procedure (A video of the monkey working on the Task-Integration Phase in Experiment 1.)	2023-04-08 16:00:58 -0400	Press to Select an action Download