Ed Yong in The Atlantic:
For years, John McGann has been studying the science of smell by working with rats and mice at Rutgers University. But when he turned his attention to humans, he was in for a shock. The common wisdom is that our sense of smell stinks, compared to that of other mammals. McGann had always suspected that such claims were exaggerated, but even he wasn’t prepared for just how acute his volunteers’ noses were. “We started with an experiment that involved taking two odors that humans can’t tell apart—and we couldn’t find any,” he says. “We tried odors that mice can’t tell apart and humans were like: No, we’ve got this.”
In a new paper, McGann joins a growing list of scientists who argue that human olfaction is nothing to sniff at. We can follow smell trails. We discriminate between similar odors and detect a wide range of substances, sometimes more sensitively than rodents and dogs can. We live in a rich world of scents and sensibility, where odors deeply influence our emotions and behavior. “I was taught in school that human olfaction isn’t a great sense,” he says. “It’s taught in introductory psychology courses and it’s in the textbooks. But this whole thing is a crazy myth.”
For this crime against olfaction, McGann accuses Paul Broca, a 19th-century French neuroscientist. Broca was a materialist who argued that the mind arose from the brain—a position that brought vigorous opposition from the Catholic Church, which believed in a separate and disembodied soul. This intellectual battle colored Broca’s interpretation of the brain.
For example, he noted that the lobes at the front of the human brain, which had been linked to speech and thought, are relatively bigger than those of other animals. By contrast, he noticed that our olfactory bulbs—a pair of structures that govern our sense of smell—are relatively smaller, flatter, and positioned less prominently.