How Has the Dog’s Brain Changed Through Selective Breeding?

A new study comparing the brains of modern dog breeds with those of more primitive dogs reveals how human-driven selection has shaped not just appearance and behavior—but also neuroanatomy.

Modern breeds show a notably larger cerebral cortex, especially the neocortex – the brain area responsible for cognition, learning, and decision-making. Importantly, the size of these areas positively correlated with learning ability.

In contrast, primitive dogs had larger amygdalae and other subcortical structures linked to emotional processing—especially fear. In their case, amygdala size was linked to reactivity and fear-based responses.

The authors argue that intense breeding over the last 200 years hasn’t just altered dogs’ bodies and colors, but also reshaped their brains toward greater behavioral flexibility, improved learning, and better cooperation with humans. In short: we’ve neuroanatomically adapted dogs to live in our world.

While the sample size was small, this is one of the first studies to show that differences between breeds go beyond temperament or activity levels—they reflect deep structural brain changes shaped by domestication and selective breeding.

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Barton, S. A., Smaers, J. B., Serpell, J. A., & Hecht, E. E. (2025). Brain-behavior differences in pre-modern and modern lineages of domestic dogs. Journal of Neuroscience, 45(21), e2032242025. doi: 10.1523/JNEUROSCI.2032-24.2025