How do higher primates provide evidence of nonlinguistic thought?

In the context of the philosophy of language, the capacity for thought is not considered exclusive to language users. While some theories once linked thought strictly to linguistic expression, it is widely accepted that nonlinguistic creatures, including higher primates, demonstrate evidence of complex cognitive processes.1

Evidence for nonlinguistic thought in higher primates includes:

• Problem Solving and Reasoning: Primates exhibit the ability to solve complex, novel problems, such as using tools in succession or in combination to reach a goal. They also demonstrate reasoning capabilities, such as transitive inference and analogical reasoning, where they can identify relationships between pairs of objects or functional concepts (e.g., matching a can to a can opener as a pair, similar to a padlock and key).23
• Mental Representation: The ability to solve spatial problems suggests that primates utilize nonlinguistic systems of representation, such as internal "maps" or "models" of their environment.1
• Concept Formation: Primates show evidence of abstract thinking, such as grasping the concept of "similarity" or "oddity" when selecting discrepant objects from a set. They also display behaviors suggesting they possess concepts for objects that extend their physical reach, such as sticks used as tools.4
• Intentionality: Observations of coordinated group behaviors—such as chimpanzees strategically positioning themselves to intercept prey—suggest that these animals act with apparent intentions to achieve specific goals.5