An experiment at Berkeley forced undergraduates to track chocolate through a field while blindfolded and crawling on their hands and knees. The good news? They proved that humans can use our noses for tracking. The bad news: video of the experiment is undoubtedly on a fetish site somewhere.
It's well-known that animals can track things by their scent, and some rely on scent more than sight to get a picture of the world. Humans, it was always assumed, didn't have the same ability to navigate by scent. A certain smell can add more information to a picture, but can't be a guide all on its own. One study shows that this is not so. Although humans may not have much practice, they can track by scent, and do so by comparing the scents that come into different nostrils.
They also do so by completely abandoning their dignity. Undergraduates at Berkeley were asked to get into a suit that blindfolded them, covered their ears, and would completely cover their hands and feet - so they could not detect a trail by sight, outside auditory cues, or touch. They were then hauled out into a field where a trail of chocolate essential oil had been laid down, leading to some chocolate. The students were filmed snuffling their way to the chocolate, which they did manage to find. When researchers compared the way the students moved to the way a dog moved when tracking down a pheasant, they noticed similar routes. While the pheasant and the chocolate trail were both relatively neat curves, the tracking trail crisscrossed the curve again and again. The trackers crossed the scent trail, sniffed to the left or right of it, turned and recrossed it.
The criss-crossing showed that both canine and human trackers managed to find the scent by using the different smells coming into each nostril. When they crossed too far to the right of the scent trail, the chocolate scent was stronger in the left nostril, they swung to the left, bringing them back to the trail. While humans might not have the full sniffing power of a bloodhound, and certainly don't have the practice, they can use their noses the same way.
(Thank you to the alert reader who emailed me this after reading our nostril dominance article to let me know that humans can track by smell.)