When early humans discovered how to build fires, life became much easier in many regards. They huddled around fire for warmth, light and protection. They used it to cook, which afforded them more calories than eating raw foods that were hard to chew and digest. They could socialize into the night, which possibly gave rise to storytelling and other cultural traditions.

But there were downsides, too. Occasionally, the smoke burned their eyes and seared their lungs. Their food was likely coated with char, which might have increased their risk for certain cancers. With everyone congregated in one place, diseases could have been transmitted more easily.

Much research has focused on how fire gave an evolutionary advantage to early humans. Less examined are the negative byproducts that came with fire, and the ways in which humans may or may not have adapted to them. In other words, how did the harmful effects of fire shape our evolution?

It’s a question that’s just starting to attract more attention. “I would say it’s mostly barroom talk at the moment,” said Richard Wrangham, a professor of biological anthropology at Harvard University and the author of “Catching Fire: How Cooking Made Us Human.” His work suggested that cooking led to advantageous changes in human biology, such as larger brains.