January 7, 2016 6:04 AM EST

Tools, language and controlled fire are often cited as critical advancements in Homo sapiens’ evolution. But in his new book, neuroanthropologist John S. Allen argues that our move into dwellings may be just as important–if not more so. Beyond providing protection from the elements and predators, homes created spaces where complex social interactions could take place and mates and offspring could become families. They also enabled early humans to sleep securely and soundly, which has been shown to increase brain functions like learning and memory formation. Dwellings are “critical not only for resting but also for thinking,” Allen writes. “By removing us from the distractions and stimuli of the outside world and providing a wholly predictable environment,” they give us “an opportunity to use our mental powers to better deal with that world.” Hence the word used to describe that feeling we get when we stray too long: homesickness.

–SARAH BEGLEY

This appears in the January 18, 2016 issue of TIME.

More Must-Reads From TIME

Contact us at letters@time.com.

You May Also Like
EDIT POST