
“You are Here” is sub-titled “Why We Can Find Our Way to the Moon But Still Get Lost in the Mall” and is a two-part book discussing how we find our way in the world and our relationship to space. Colin Ellard’s “You are Here” focuses much of his attention on indigenous societies, birds, insects, bees, and ants and their extra-ordinary senses of direction. The second half of the book focuses on how human beings interact with space.
The research Ellard cites in “You are Here” about ants in particular is fascinating to me, mostly because of how the experiments were performed. In one experiment, the ant subjects were en route back to their nest when the researchers picked them up and moved them. The idea was to see if the ants could still find their way back to the nest through their sense of smell; the ants—like most of us would be if we were in that situation—were unable to find their way back and found themselves off-course. This proved to the researchers that the ants weren’t using a sense of smell, but something different. Instead, researchers speculated that the ants were using a complex system called “path navigation” that enables ants to keep track of their movements and distances so that can find their way back to a point of origin.
In another experiment that sounds just as tortuous, the ant subjects were given tiny backpacks to carry with four times their weight. The purpose of this particular experiment was to see if the ants determined their “path navigation” by estimating a unit of effort. The ants made it back just fine, indicating that the extra weight had no bearing on their sense of direction.
There are a few other possibilities that could account for how well ants navigate. One is “optic flow” which is the measurement of “flowing distance”. Another idea—perhaps the strangest that I read---is that the ants count their own steps. The experiment to prove or disprove this particular theory is just as ridiculous as the others—the ants were given little tiny stilts to walk with. Predictably, the ants stumbled around and lost their way, which means that it is possible that ants count their own steps.
Unlike ants, homing pigeons usually do find their way even if they are taken off-course. There is evidence to suggest that homing pigeons find their way through a sort of internal magneticcompass that somehow maps the earth’s magnetic fields. To test this, some birds were given coils to wear around their necks which the researchers believed would drastically interfere with the birds abilities to navigate. The study was inconclusive as only the young novice homing pigeons had trouble, while the more experienced birds were still able to find their way around.
Some researchers believe that homing pigeons’ photoreceptors—located behind the eyes of the pigeons—might be able to see magnetic fields. Another idea is that homing pigeons have the ability to see (or envision, I’m not exactly clear) a geo-gradient map which includes smells, lights, and magnetic fields.
