Baboons (Papio papio) Process a Context-Free but Not a Context-Sensitive Grammar

Area of Science:

• Cognitive Science
• Animal Behavior
• Linguistics

Background:

• Human language uniquely utilizes supra-regular grammars, exceeding regular grammar complexity.
• The capacity for mastering supra-regular grammars is hypothesized as a uniquely human trait.

Purpose of the Study:

• To investigate baboons' ability to learn context-free and context-sensitive grammars.
• To compare baboon and human learning of supra-regular grammars.

Main Methods:

• Baboons and humans participated in a prediction task involving tracking a moving target on a touchscreen.
• Sequences of target locations followed either a context-free (mirror) or a context-sensitive (repeat) grammar, with rare violations.
• Response times were measured to detect learning and sensitivity to grammatical violations.

Main Results:

• Baboons exhibited slower response times to violations in mirror sequences (context-free grammar).
• Baboons did not react to violations in repeat sequences (context-sensitive grammar).
• Humans successfully learned both context-free and context-sensitive grammars.

Conclusions:

• Baboons demonstrated sensitivity to context-free grammars but not context-sensitive grammars.
• These findings suggest a difference in grammatical processing abilities between baboons and humans.
• The capacity for complex, context-sensitive grammar learning may be a distinguishing feature of human cognition.