Fly out-smarts man
This challenges the assumption that human language complexity is unique and foundational to intellect, with implications for evolutionary biology and linguistics, though it is incremental in applying existing formal methods to a new domain.
The study tackled the problem of understanding the complexity of Drosophila's precopulatory courtship body language by translating it into a formal language using symbolic dynamics and comparing it to human languages via Chomsky's hierarchy. The result showed that Drosophila's body language is at least as powerful as human languages, indicating that human intellect is not directly due to formal grammar complexity.
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.