Behavioral and Brain Sciences

Open Peer Commentary
Heyes, C. M.: Theory of mind in nonhuman primates

Assessing theory of mind with nonverbal procedures: Problems with training methods and an alternative “key” procedure

Juan Carlos Gómez a1
a1 School of Psychology, University of St. Andrews, St. Andrews KY16 9JU, United Kingdom


This commentary criticizes nonverbal methods of assessing theory-of-mind on the basis of prior training of the critical response because they would encourage simple, nonmentalistic, associative solutions even in subjects with mentalistic capacities. I propose instead a new experimental paradigm based upon the use of spontaneous responses in less artificial situations. This method has already provided positive evidence of some level of ToM understanding in nonhuman primates.