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Related Experiment Video

Updated: May 1, 2026

Assessment of Social Cognition in Non-human Primates Using a Network of Computerized Automated Learning Device ALDM Test Systems

Assessment of Social Cognition in Non-human Primates Using a Network of Computerized Automated Learning Device ALDM Test Systems

Published on: May 5, 2015

Symbol addition by monkeys provides evidence for normalized quantity coding.

Margaret S Livingstone¹, Warren W Pettine, Krishna Srihasam

¹Department of Neurobiology, Harvard Medical School, Boston, MA 02115.

Proceedings of the National Academy of Sciences of the United States of America

|April 23, 2014

Summary

This summary is machine-generated.

Monkeys learned to combine symbolic rewards, demonstrating a unique calculation method. Their reward scaling was neither linear nor compressed, but dynamic and relative.

Keywords:

macaque normalization number sense value coding

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Published on: August 1, 2018

Area of Science:

Cognitive neuroscience
Animal behavior

Background:

Weber's law describes sensory perception.
Two models explain it: compressive scaling or proportional variability.
Distinguishing these requires understanding quantity addition/subtraction.

Purpose of the Study:

To investigate how Rhesus monkeys combine symbolically represented reward magnitudes.
To determine if monkeys perform symbolic calculation or rote memorization.
To characterize the scaling of symbolic reward representation.

Main Methods:

Rhesus monkeys were trained to associate 26 symbols with 0-25 drops of reward.
Monkeys were tested on their ability to combine these symbols.
Performance was assessed with novel symbol sets to test for generalization.

Main Results:

Monkeys successfully combined symbolically represented reward magnitudes.
This ability transferred to novel symbol sets, indicating calculation.
Symbolic reward combination followed a dynamic, relative scaling, not linear or compressed.

Conclusions:

Monkeys can perform symbolic arithmetic on reward magnitudes.
This suggests a flexible cognitive system for quantity representation.
The findings challenge existing models of sensory scaling and Weber's law.