In this theoretical contribution, led by José Miguel Martínez Gázquez, Thomas Castelain, and Miquel Llorente from the Comparative Minds Research Group, the authors propose an integrative evolutionary framework suggesting that language may have functioned as a stabilizing force on pre-existing motor asymmetries, contributing to the consolidation of population-level right-handedness in humans.

The article synthesizes evidence from comparative primatology, developmental psychology, cognitive neuroscience, and evolutionary theory. Grounded in Tinbergen’s four questions and informed by a gene–culture coevolution perspective, the framework argues that motor asymmetries are widespread across species and represent deep biological roots of lateralization. However, the emergence of language —together with its cultural transmission and social embedding — may have amplified, reinforced, and stabilized these asymmetries within the human lineage.

A central argument of the paper is the distinction between structural brain asymmetries and functional lateralization as expressed in behavior. Rather than equating anatomical asymmetries directly with handedness, the authors emphasize how language production systems, communicative gestures, and praxis-related neural networks interact dynamically. In this view, linguistic behavior and manual action share overlapping neural substrates that may have co-evolved and mutually constrained one another during human evolution.

By integrating comparative findings from non-human primates, the article situates human handedness within a broader evolutionary continuum. Evidence from gestural communication and motor preferences in other primates shows that asymmetries predate language but may have been reorganized and stabilized through linguistic pressures. This approach moves beyond human-centered explanations and frames lateralization as a gradual, phylogenetically embedded phenomenon.

Developmentally, the framework also highlights how early communicative behaviors —including gesture, vocal production, and emerging linguistic capacities —may contribute to the shaping and consolidation of handedness patterns across ontogeny. This reinforces the idea that lateralization is not fixed at birth but emerges through interaction between biological predispositions and environmental and cultural factors.

This publication forms part of our ongoing research program examining the evolutionary and developmental relationships between gestural communication, language emergence, motor control, and hemispheric specialization. It aligns with our broader objective of understanding how communicative systems and brain asymmetries co-structure each other across evolutionary time and individual development.

The article is available in open access at:

Gázquez, J. M. M., Castelain, T., & Llorente, M. (2026). Language as an evolutionary pressure of human handedness. Acta Psychologica, 264, 106489. https://doi.org/10.1016/j.actpsy.2026.106489