Fly out-smarts man

TL;DR

This study models Drosophila's precopulatory courtship body language as a formal language, revealing it is at least as complex as human languages, challenging assumptions about the link between language complexity and intelligence.

Contribution

It introduces a mathematical symbolic dynamics approach to analyze Drosophila courtship, demonstrating its body language has comparable formal language complexity to humans.

Findings

Drosophila body language can encode individual information.

Drosophila's language complexity matches that of human languages.

Human intelligence is not solely determined by language complexity.

Abstract

Precopulatory courtship is a high-cost, non-well understood animal world mystery. Drosophila's (=D.'s) precopulatory courtship not only shows marked structural similarities with mammalian courtship, but also with human spoken language. This suggests the study of purpose, modalities and in particular of the power of this language and to compare it to human language. Following a mathematical symbolic dynamics approach, we translate courtship videos of D.'s body language into a formal language. This approach made it possible to show that D. may use its body language to express individual information - information that may be important for evolutionary optimization, on top of the sexual group membership. Here, we use Chomsky's hierarchical language classification to characterize the power of D.'s body language, and then compare it with the power of languages spoken by humans. We find that from a formal language point of view, D.'s body language is at least as powerful as the languages spoken by humans. From this we conclude that human intellect cannot be the direct consequence of the formal grammar complexity of human language.