Theory of mind tested by implicit false belief: a simple and full‐fledged mental state attribution

About 40 years have passed since ‘theory of mind (ToM)’ research started. The false‐belief test is used as a litmus test for ToM ability. The implicit false‐belief test has renewed views of ToM in several disciplines, including psychology, psychiatry, and neuroscience. Many important questions have been considered via the paradigm of implicit false belief. We recently addressed the phylogenetic and physiological aspects of ToM using a version of this paradigm combined with the chemogenetic technique on Old World monkeys. We sought to create animal models for autism that exhibit behavioral phenotypes similar to human symptoms. The simultaneous manipulation of neural circuits and assessments of changes in phenotypes can help identify the causal neural substrate of ToM.