Experts have longsuspected that complex social interaction drove the evolution of large brains in humans. Now a study in wasps supports and refines that theory: it seems that dominant individuals have larger brain regions responsible for higher-order cognitive processes.
Biologists at the University of Washington observed the behavior of paper wasps (Mischocyttarus mastigorphorus) in the Costa Rican rain forest and then measured the size of their brains. The researchers found that the so-called mushroom bodies, the lobes that underlie learning and memory in insects, were larger in dominant wasps than in their subordinate peers.
Mushroom bodies are the insect equivalent of the human neocortex, the outer layer of our brain, which handles complex cognition. Scientists have already established that the neocortex and the mushroom bodies are larger in social species such as humans and wasps, as compared with solitary animals such as bears and lone spiders. The new study suggests that competition for rank may have been a key factor in the evolution of this intelligence.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
This story was originally printed with the title, "Big Brains Dominate".
Subscribe to Support Independent Journalism
Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.
When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.
Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber
