Out of Our Depth

One of the things that two different eyes gives us is the ability to use our binocular vision for depth perception. People who have only one working eye or who may have one very dominant eye have more trouble judging the distance of things than those whose eyesight is evenly matched. People who have been blind for some time who may have their sight surgically restored often take some time to learn how to judge distance based on visual cues.

Are we born with this depth perception, though, or do we learn it the way we learn to walk and learn to talk? In the early 1960s, two researchers conducted tests first with human babies to learn if they had to develop the ability to judge distance and thus lessen their chances of falling or grabbing for something and either smacking it because it was too close or missing it because it was too far away.

It turns out that babies probably begin to develop the ability to judge distances visually at about the same time they start to move around enough that they could fall off something and hurt themselves. The researchers found that animals which are mobile from birth or at a very early point in their lives had that ability much sooner than human infants.

It seems only fair that animals develop the ability to perceive depth much earlier than do people, as people develop the ability to be relentlessly, ridiculously shallow -- take any Kardashian as an example -- long before animals do.