Our Sense Of Smell Is Better Than Originally Thought

Biology textbooks are riddled with passages relating how bad humans are at perceiving odors. As the oft-quoted statistic goes, humans can only perceive '10,000 odors', a number that sits particularly well with some dog-lovers, who like to remind us that canines have 300 million odor receptors, while humans only sport 6 million. But a study in 2014 revealed that humans might not be as olfactorily challenged as we once thought because, as it turns out, we can perceive more than 1 trillion odors—and that's a conservative estimate. ¹ The original belief that humans' sense of smell is worse than that of other animals—dogs, mice, moles and even sharks was based on a 19th century hypothesis about free will that has more in common with phrenology than with our modern understanding of how brains work. John McGann, a neuroscientist who studies olfaction at Rutgers University, recently revealed how we ended up with this myth. The truth is humans are actually pretty good at smelling our world. ²