Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.10.05.756726

Non-trivial compositionality in chimpanzees: an experimental demonstration

Le Fur, A.·Lemasson, A.·Townsend, S. W.·Leroux, M.
View original source ↗Export metadata ↓

Abstract

Compositional syntax - the ability to combine meaningful units into structured sequences whose overall meaning depends on both the meanings of the parts and their combination - is a hallmark of human language. Recent work suggests that chimpanzees may exhibit similar capacities, raising the possibility that compositionality predates the emergence of language in humans. However, a key challenge has been to exclude simpler explanations in which call combinations are processed as independent utterances rather than integrated structures. Here, we address this issue using a source-manipulation paradigm in playback experiments with captive chimpanzees (n = 6) at the Sigean African Reserve, France. We presented sequences combining alarm and recruitment calls either from a single source (one loudspeaker) or from two spatially distinct sources (two loudspeakers). If sequences are interpreted as independent calls, responses should not differ between conditions. Instead, chimpanzees responded significantly faster when sequences originated from a single source. Bayesian survival analyses confirmed this effect. These results support a non-trivial form of compositionality, whereby the meaning of call combinations depends on their integration into a unified sequence produced by a single individual. Our findings provide experimental evidence that key features of linguistic compositionality may have evolutionary roots in the primate lineage.

Explore related subjects

animal behavior and cognitionPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Le Fur, A., Lemasson, A., Townsend, S. W., Leroux, M.. 2026-10-11. Non-trivial compositionality in chimpanzees: an experimental demonstration. https://doi.org/10.64898/2026.10.05.756726

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Characterizing risky play-like behaviour in juvenile versus young adult rats

Play is an evolutionarily conserved behaviour that contributes to healthy behavioural and neural development. While animal play is traditionally categorized as locomotor, object, or social play, developmental research in children has highlighted the importance of risky play, defined as voluntary engagement with uncertainty and manageable physical risk. Whether similar forms of behaviour occur in non-human animals remains largely unexplored. The present study aimed to establish an ethological framework for identifying and quantifying risky play-like behaviour in rats. Juvenile and young adult male Lister Hooded rats were repeatedly exposed to a custom-designed environment containing elevated and unstable structures that provided opportunities for climbing, balancing, hanging, jumping and social interaction. Behaviour was quantified using two complementary ethograms: a location-based ethogram describing the animal's position within the apparatus and a risky event ethogram capturing selected behaviours associated with physical challenge. By comparing the behaviour of animals during the natural peak of play behaviour with animals beyond this developmental period, we aimed to evaluate whether engagement with elevated and unstable environments reflects play-related processes rather than environmental complexity alone. This study provides a behavioural framework for investigating risky play-like behaviour in rodents and establishes a foundation for future studies examining its developmental and neurobiological significance.

animal behavior and cognition↗
bioRxiv2026

Sensitive period for song learning outlasts parent-offspring cohesion in wild zebra finches

Communication is central to social behaviour, with vocalisations playing a crucial role in many species. In some species, vocalisations are learned, with songbirds being key to understanding vocal learning. The Australian zebra finch (Taeniopygia castanotis) is the most studied model organism for vocal learning. In captivity, juveniles are typically housed with their father, where males learn their father song and females develop a preference for that song. In nature, however, the social structure of zebra finches is more dynamic across space and time. To identify the natural social conditions during song learning, we followed zebra finch families across their early life in the wild using automated radio-tracking. The distance between juveniles and their parents increased post-fledging and became similar to the distance between juveniles and unrelated adults by the second half of the song learning period. These findings indicate a highly dynamic social environment during the song learning period and suggest that juvenile males could learn from many tutors and that females may develop broader song preferences. Thus, studies based on one-tutor paradigms should be interpreted carefully with respect to functional implications and highlight that future vocal learning studies could better reflect the social conditions under which song develops.

animal behavior and cognition↗
bioRxiv2026

Data-driven frame-by-frame analysis of surface swimming and terrestrial walking in the coastal beetle Phaleria atriceps

Background. Inter-leg coordination of insects changes depending on environmental conditions. Although locomotor changes between terrestrial and aquatic environments have been examined in various insects, relatively little is known about coastal insects living at the boundary between these environments. We therefore compared the inter-leg coordination during terrestrial walking with that during surface swimming in the coastal beetle Phaleria atriceps. Methods. Surface swimming was recorded in 17 individuals and terrestrial walking in 10 individuals using high-speed video at 1,000 frames/s. The six leg tips and anterior and posterior body landmarks were tracked frame-by-frame using DeepLabCut, and leg movements were quantified in a body-centered coordinate system. Leg movement periods were estimated from sinusoidal fits to longitudinal leg-tip trajectories. Inter-leg phase relationships were calculated for all 15 leg pairs and integrated to reconstruct a representative six-leg phase organization for each locomotor mode. Results. Leg movement periods were significantly longer during surface swimming than during terrestrial walking for all six legs. During walking, the six-leg phase relationship closely matched an alternating tripod pattern, with a left foreleg (L1), a right middle leg (R2), and a left hind leg (L3) forming one phase group and a right foreleg (R1), a left middle leg (L2), and a right hind leg (R3) forming the opposing group. The same broad grouping was observed in the six-leg phase relationship during surface swimming, although significant differences in relative phase were detected for L1-L2, L1-R2, and R1-R2. Conclusions. Phaleria atriceps exhibited six-leg phase relationships broadly consistent with an alternating tripod pattern during both terrestrial walking and surface swimming, whereas leg movement periods and certain inter-leg phase relationships differed between the two locomotor modes. These findings provide a quantitative description of the similarities and differences in inter-leg coordination between terrestrial walking and surface swimming in a coastal beetle. Further mechanical and comparative studies will be needed to clarify the functional and evolutionary significance of these findings.

animal behavior and cognition↗