Recursion: what is it, who has it, and how did it evolve?

Area of Science:

• Linguistics
• Cognitive Science
• Evolutionary Biology

Background:

• Recursion in linguistics is controversial due to varied definitions and features like universality and uniqueness to human language.
• Current understanding includes two main senses: phrase embeddedness for long-distance dependencies and output string specification (meta-recursion).

Purpose of the Study:

• To explore the controversial topic of recursion in linguistics.
• To delineate different definitions and evolutionary scenarios of recursion in human language.
• To examine the adaptive value and cognitive underpinnings of recursive language abilities.

Main Methods:

• Literature review and synthesis of existing research on recursion in linguistics and cognitive science.
• Analysis of differing theoretical positions on the definition and evolution of recursion.
• Examination of proposed evolutionary scenarios, including gradualist and saltationist perspectives.

Main Results:

• Identified two primary definitions of recursion: phrase embedding and output string specification.
• Presented two contrasting evolutionary scenarios: gradualist (communication-focused) and saltationist (non-communication-focused).
• Highlighted cognitive prerequisites like Theory of Mind and working memory capacity linked to recursion's evolution.

Conclusions:

• Recursion's definition and evolutionary origins remain subjects of significant debate in linguistics.
• Understanding recursion requires considering both its structural properties and its potential adaptive advantages for cognition and communication.
• Further research is needed to fully elucidate the evolutionary trajectory and functional significance of recursion in human language.