Motor-sensory biases are associated with cognitive and social abilities in humans

Scientific Reports volume  14, Article number: 14724 (2024 ) Cite this article

Across vertebrates, adaptive behaviors, like feeding and avoiding predators, are linked to lateralized brain function. The presence of the behavioral manifestations of these biases are associated with increased task success. Additionally, when an individual’s direction of bias aligns with the majority of the population, it is linked to social advantages. However, it remains unclear if behavioral biases in humans correlate with the same advantages. This large-scale study (N = 313–1661, analyses dependent) examines whether the strength and alignment of behavioral biases associate with cognitive and social benefits respectively in humans. To remain aligned with the animal literature, we evaluate motor-sensory biases linked to motor-sequencing and emotion detection to assess lateralization. Results reveal that moderate hand lateralization is positively associated with task success and task success is, in turn, associated with language fluency, possibly representing a cascade effect. Additionally, like other vertebrates, the majority of our human sample possess a ‘standard’ laterality profile (right hand bias, left visual bias). A ‘reversed’ profile is rare by comparison, and associates higher self-reported social difficulties and increased rate of autism and/or attention deficit hyperactivity disorder. We highlight the importance of employing a comparative theoretical framing to illuminate how and why different laterization profiles associate with diverging social and cognitive phenotypes.

Although human cognition appears unique on the surface, it is supported by more general motor-sensory processing common across other species. While both sides of the brain are engaged across all instances of behavior, motor-sensory dominances are a fundamental principle of the two hemispheres of the vertebrate brain (see1). Evidence from comparative vertebrate studies demonstrates that individual-level motor-sensory biases are associated with increased cognitive capacity (e.g., measured by task performance). Furthermore, alignment of an individual’s motor-sensory bias (i.e., right vs. left) with the direction of the majority of the population confers a social benefit (e.g., group cohesion as in shoaling)2,3,4,5. Despite these patterns across a variety of vertebrate taxa, it is not yet clear if motor-sensory biases in the human brain influence cognitive capacity and social abilities.

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