Time and Space May Be Perceived by a Common Brain System
People and animals may use shared brain mechanisms to judge time and space.
Posted November 25, 2018
Time and space are fundamental dimensions of the universe. Those dimensions are conventionally scaled by distinctly different methods of measurement. We use hourglasses and watches to record the passage of time; we use rulers and gauge blocks to index length. Yet, Albert Einstein’s revolutionary theory of relativity upset this simplistic apple cart by suggesting that time and space are actually inseparable.
Einstein’s startling suggestion certainly challenges common sense. Nevertheless, research in cognitive science and neuroscience has recently revealed that we use a shared neurobiological mechanism to make psychological judgments of time and space.
In one key piece of behavioral evidence, researchers found that the longer the temporal duration of a line, the longer in spatial length people reported it to be. In a parallel fashion, the longer the spatial length of a line, the longer its temporal duration people reported it to be. This surprising interdependence violates the belief that—at least psychologically—space and time are independent dimensions.
Furthering the unexpected nature of this finding is the fact that rhesus monkeys responded in the same way as did people when given comparable testing procedures. Clearly, the psychological interdependence of space and time is not uniquely human. Nevertheless, as primates, both monkeys and humans share key neural structures like the cerebral cortex.
In our own research at The University of Iowa, we sought to advance our understanding of the common processing of time and space by attempting to replicate the psychological interdependence of space and time in the pigeon—an animal which, like all birds, does not have a cerebral cortex. Remarkably, pigeons behaved just as did humans and monkeys: the longer the temporal duration of a line, the longer in spatial length pigeons reported it to be and the longer the spatial length of a line, the longer its temporal duration pigeons reported it to be.
When adaptive behaviors are shared by extremely distant phylogenetic relatives, it is generally assumed that their evolution independently arose in response to common survival demands. Exactly what may have encouraged the common processing of time and space by birds and mammals has yet to be determined. Still, it is clear that the very differently organized brains of birds and mammals exhibit a common functionality: a finding that is turning out to be more common than is conventionally expected.
Indeed, the cognitive prowess of birds is now deemed to be ever closer to that of both human and nonhuman primates. Those avian nervous systems are capable of far greater achievements than the pejorative “bird brain” would ever have suggested.
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