We are often told that there are no shortcuts in life. But the brain—even the brain of a rat—is wired in a way that completely ignores this kind of advice. The organ, in fact, epitomizes a shortcut-finding machine.
The first indication that the brain has a knack for finding alternative routes was described in 1948 by Edward Tolman of the University of California, Berkeley. Tolman performed a curious experiment in which a hungry rat ran across an unpainted circular table into a dark, narrow corridor. The rat turned left, then right, and then took another right and scurried to the far end of a well-lit narrow strip, where, finally, a cup of food awaited. There were no choices to be made. The rat had to follow the one available winding path, and so it did, time and time again, for four days.
On the fifth day, as the rat once again ran straight across the table into the corridor, it hit a wall—the path was blocked. The animal went back to the table and started looking for alternatives. Overnight, the circular table had turned into a sunburst arena. Instead of one track, there were now 18 radial paths to explore, all branching off from the sides of the table. After venturing out a few inches on a few different paths, the rat finally chose to run all the way down path number six, the one leading directly to the food.
Taking the path straight to the food cup without prior experience may seem trivial, but from the perspective of behavioral psychologists at the time, the rat’s navigational accomplishment was a remarkable feat. The main school of animal learning in that era believed that maze behavior in a rat is a matter of simple stimulus-response associations. When stimuli in the environment reliably produce a successful response, neural connections that represent this association get strengthened.
In this view, the brain operates like a telephone switchboard that maintains only reliable connections between incoming calls from our sense organs and outgoing messages to the muscles. But the behavioral switchboard was unable to explain the ability to correctly choose a shortcut right off the bat without having first experienced that specific path. Shortcuts and many other intriguing observations along these lines lent support to a rival school of thought promulgated by theorists who believe that in the course of learning, a map gets established in a rat’s brain. Tolman—a proponent of that school—coined the term: the cognitive map.
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