Want to be impressed by the natural athletic abilities of your dog? Try this: first focus her attention on a favorite ball or other bouncing toy while positioning yourself at least several feet away from her. Make sure that the dog is happily agitated, displaying signs of excitement and interest. Then throw the ball towards your dog at a moderate rate of speed (think of tossing your car keys to a friend, not rocketing a baseball in from the warning track), causing it to bounce a foot or less in front of her.
I predict that your dog will, in one fluid series of motions, visually track the ball from your hand through its flight path, maneuver her muzzle such that the ball (after changing directions only a short distance in front of her) travels directly towards her snout, open her jaws wide enough to allow the ball to enter, and then clamp her jaws down on the ball, securing it like an NFL wide receiver.
Now let me give you some free advice: don’t attempt this stunt with a human friend or family member, unless you also want to test your first aid skills. They don’t stand a chance of pulling it off, regardless of the amount of painful practice they rack-up.
So how can dogs make this difficult athletic task appear so simple?
It’s all about the natural physiology of their eyeballs. The cells in mammalian eyeballs (called “photoreceptors”) process light waves and transmit the translated information to the brain, producing images of the observed world in the mind’s eye. This transmission process occurs very quickly, but it is not instantaneous. As a result, what we perceive as a seamless torrent of visual data is really a series of rapidly-changing still images. The rate at which those individual images are communicated to the brain is called the “flicker fusion rate.” This phenomenon is the reason why old-timey motion pictures appear choppy rather than seamless–the individual images are presented at a rate that is slower than our human flicker fusion rate.
According to Alexandra Horowitz, psychology professor and author of “Inside of a Dog — What Dogs See, Smell, and Know,” while the human flicker-fusion rate usually hovers at around sixty cycles per second, dogs employ a significantly higher rate (somewhere between “seventy and eighty stills per second”). This adaptation allows dogs to track swiftly-moving objects (like Frisbees) more effectively than we do–they can see the new location of an object in motion a split-second before we can. As a result, they can react by re-positioning their body to account for the new location of the object while we would still be waiting for the new image to register.
Don’t believe me? Go take your dog outside for an extended session of “fetch” the next time you see her. She’ll come back happy and exhausted and you’ll come back impressed and humbled.