In songbirds, complex vocal learning predicts problem-solving abilities and brain size

Vocal learning complexity, or the ability to imitate sounds, is associated with better problem-solving abilities and larger brains in songbird species, according to a new study. Whether vocal learning complexity was linked with such cognitive phenotypes was previously unknown. The approach used in the study, to study a lineage of birds, serves as a model for testing similar patterns in other vocal learning species. Complex vocal learning – the ability to imitate heard sounds – is a crucial component of human spoken language and has been assumed to be associated with more advanced cognitive abilities. Outside of humans, it has been observed in a small number of taxa, including songbirds. However, while vocal learning taxa that display the most complex vocal learning behaviors are often also thought to exhibit more intelligent cognitive capacities, the association – if any – has not been quantitively tested across species. To test whether there is a linkage between vocal learning complexity and other cognitive or physiological traits, Jean-Nicolas Audet and colleagues performed a suite of behavioral experiments across 214 individual birds of 23 bird species – 2 domesticated species, 19 wild-caught songbird species, and two non-vocal learning species. Audet et al. combined published data on the species’ vocal behaviors and evaluated 4 measures of each bird’s cognitive ability, specifically problem-solving, associative and reversal learning, and self-control. They discovered that species with the most complex vocal learning aptitude demonstrated better problem-solving skills and possessed relatively larger brains. What’s more, the authors found that the robust relationship between vocal learning abilities, problem-solving, and brain size persisted, even when considering individual variation, phylogeny, and other potentially confounding non-cognitive variables.