Humans can track scents like dogs, if they abandon all dignity

By Nicholas Wade Published: December 18, 2006
Interantional Herald Tribune

Imagine that, by one of life's more serious vicissitudes, you had to serve as someone's dog. Cheer up: you would do better than you think, at least at what might seem the hardest part of the job, tracking a scent.

Researchers at the University of California, Berkeley, have found that people can follow a scent surprisingly well, as long as they do not mind abandoning all dignity, putting their nose right to the ground and crawling along with their bottoms in the air.

But the achievement, as Samuel Johnson remarked in another context, is "like a dog's walking on his hind legs. It is not done well; but you are surprised to find it done at all."

The researchers' subjects, asked to track a chocolate scent across a meadow, inched along at a speed of, well, one inch a second. Though their pace accelerated to two inches a second after a few training sessions, it seems clear enough why trackers like the Bushmen of the Kalahari relied on eyesight to follow an animal's trail.

The researchers did not run a dog versus human competition because the dogs were in a different league, sometimes smelling a dragged target (a dead bird) from the starting line and making a beeline for it.

The purpose of the experiment was to inquire whether having two nostrils spaced slightly apart helps track a scent, just as having two ears enables the brain to locate the source of a sound. But dogs cannot report what they are doing and object to procedures like having one nostril blocked. So the Berkeley researchers, led by Noam Sobel and Jess Porter, chose more docile experimental animals: psychology department undergraduates.

The undergraduates, as they warmed to the task, spontaneously mimicked some of the behavior of tracking dogs, like sniffing faster to take in more olfactory information.

Dr. Sobel said it was not a huge surprise to find that people could track a scent, but no one had systematically tested the possibility.

Catherine Dulac, an expert at Harvard on smell and behavior in mice, said that after reading the reappraisal of human olfactory abilities, "I had such a good laugh." The ability followed, Dr. Dulac said, from the design of the olfactory system, which perhaps holds more surprises. "There might be many more things we can do with our nose," she suggested.