One early morning my mother and I set out in kayaks on the lake, through the morning mist. It was beginning to lift, and we planned to stay close to shore. We’d been paddling for about ten minutes, looking up at the cottages—most of them still quiet and dark—when that cloud of moisture that surrounded us suddenly seemed to thicken. It was a neat sensation, to be sure, but we also couldn’t see half a metre in front of us. We waited it out for a while and then figured our keen senses of direction should guide us to shore. It was in plain sight not a few minutes ago, after all.
We were wrong about that. We paddled for a few minutes and never seemed to make ground. And when the fog did lift, we were smack in the middle of the lake with our noses pointing the opposite direction of our cottage.
What might have helped our plight? Sure, a GPS or compass. How about a good sniffer? If someone back at our cottage had bacon sizzling on the stove, the familiar smell might just have guided us to shore. But new research suggests that (bacon or no bacon) just having a keen sense of smell might mean that we are also better equipped for navigation.
A study released in October in Nature Communications showed that olfactory senses are related to spatial sense. So, it’s not just about being able to follow a scent to a specific location. Rather, having the ability to pick up that scent means you’re probably better at getting to that spot in the first place.
The researchers, out of McGill University, tasked a group of participants with finding their way through a virtual city. Given the location of certain landmarks, they had to orient themselves and make their way from one point to another. Those same participants were given a range of scented felt-pens and had to identify the smells. Those who did well in one exercise also excelled in the other.
The researchers linked this back to two parts of the brain, the left medial orbitofrontal cortex (mOFC) and the right hippocampus. These areas are both critical to a sense of smell, but the mOFC hadn’t yet been shown to have such a significant tie to navigation. The study found a larger right hippocampus and thicker left mOFC in test participants who excelled at identifying scents and navigating the virtual city—suggesting these regions have developed in tandem. Those who were poor navigators, the study found, also scored lower on identifying scents.
If you’re thinking, ‘I could make the drive up to the cottage with my eyes closed, but I wouldn’t know the smell of coffee in the morning from a steak on the barbecue at night,’ there’s a reason for that too. The study’s correlation is specific to spatial sense and cognitive mapping, but that’s only one way people make their way in the world. The other strategy people use is called stimulus-response, and it comes from repeating the same activity, driving or walking the same route, and creating motor-actions based on cues: turn right at the exit just passed the bait shop, turn left after the bridge. This strategy for navigating is learned, and it’s not known to be connected to scent.
The study supports a recent theory that scent has developed out of a need to navigate. When we think of animals whose scent is their primary means for sourcing food or identifying potential threats, this makes a lot of sense (pardon the pun). For us humans that lack a strong sense of smell, we can be grateful for that GPS.