Animals have all kinds of way-finding capacities built into their various bodies, and many of these navigational systems are far more sophisticated than any human counterpart. Monarch butterflies make their journey to Mexico using the angle of the sun as a compass, in combination with what scientists believe may be an internal body clock operating with a circadian rhythm. Dung beetles navigate via the Milky Way galaxy. Homing pigeons have tiny iron oxide crystals in the skin lining their upper beak that function as sensors for the earth’s magnetic field. Sea turtles swim across vast oceans and, using geomagnetic cues, are able to land at the very nest where they were born decades earlier.
We humans do have some internal navigational abilities of our own, independent of external technologies like GPS, paper maps, and magnetic compasses. In fact, our brains constantly create mental maps that unconsciously calculate our location. The scientific study of these cognitive maps originated in lab experiments in the 1940s involving rats. American behavioral psychologist Edward Tolman broke new ground when he discovered that rats operate on more than just reward/punishment stimulus. They actually process information and make navigational decisions based on knowledge of their surrounding environment. When Tolman replaced a maze where the rats were accustomed to receiving food at the end with one that had many of the previous paths altered or blocked, the rats demonstrated that they had made a mental representation or map of their environment and knew their way to the same exit.
Tolman went on to propose that humans have complex cognitive maps as well, shaped by cues acquired by noticing landmarks. We construct mental representations or images of different environments we inhabit, he argued, and these mental maps help situate us. When I am restless and struggling to fall asleep, for example, I can draw on details of spatial maps in my head of a favorite park, a lovely vacation, or my childhood home. The visualization of these pleasant environments, thoroughly mapped out and residing in what Tolman called the “central office” of the brain (the hippocampus), is often all it takes for me to move from restlessness to sleepiness.
