20 years ago, my marketing professor was talking about scent being the sense most strongly linked with memories. The smell of exhaust taking him back to his cou

20 years ago, my marketing professor was talking about scent being the sense most strongly linked with memories. The smell of exhaust taking him back to his country of origin. Sticking with medical smells, my sister can smell bladder cancer. Not sure how common that is, but she used to work in urology and after a urine sample was turned in, she could tell ahead of time who was sick. I imagine that smell has helped shape how we find food and avoid disease and has been reinforced since some long ago ancestor likely common to many mammals or even further back. We often think of dogs or bears for their well developed sense of smell or even sharks sensing blood in the water. Fun fact: humans are more sensitive to the smell of petrichor (fresh rain on dry ground) than sharks are to blood.