Most of us have experienced the frustration of seeing a film on the computer hacked into different still images because the computer couldn't process the information fast enough to give us a fluid picture of the movie. Once the computer gets up to speed — that speed being twenty-four images flashed at us for every second we're watching — we see motion, not pictures. Sped up a little faster, and we'd still see motion, not pictures. We wouldn't be able to distinguish between one and the other. That is the limit of our temporal resolution, or the number of times our mind and eyes can 'update' the picture we're seeing.

Temporal resolution measures how well we can tell two stretches of time apart, using our eyes. There are many animals that do it better than we do.


Birds' eyes, for example, have excellent temporal resolution. Their critical flicker frequency - the term used to denote when our eyes convert a series of light changes into continuous motion - is much higher than any human's CFF. This lets them see any change in the light, generally caused by motion of some kind, much faster and more accurately than we can. We're not just talking about graceful, gliding birds of prey. A test done on chickens showed that they had a critical flicker frequency of 43 to 83 cycles per second — that's well above a human's CFF.

Our feathered friends' facility with temporal resolution may come from the structure of the cones in their eyes. Birds have an odd 'double cone' structure in their eyes that allows them to detect ultraviolet light. Studies showed that chickens managed higher CFFs than humans when they were exposed to both visible and UV light. A lack of either light slowed them down. Birds' eyes are also larger and have a higher density of rods and cones, which may fire off signals to the brain more continuously than the cells in human eyes do.

This double cone structure is shared by certain reef fish and octopuses, who may very well share birds' abilities to notice movement and flickers before humans can. There could be any number of animals that see the world change faster than we do.

But birds don't just kick human ass in the visual department. They also have different auditory temporal resolution. Birds were able to detect differences in harmony and tone about twice to four times as fast as human subjects. That's right: chickens hear and see faster than you do.


Which brings me back to the most crucial insight offered by these studies: Why don't birds ever go to the movies? You've always wondered. You know you have.

The problem is that movies are made for human levels of temporal resolution. Take a bird to a movie and it see the film as a progression of slides. Plus, it will hear the audio problems, or the warbles in an actor's voice, long before we will. Add to that the fact that it will see the film in much different colors, if any UV light is bouncing off the screen, and you can understand why movie theaters are not full of chickens. At last, one of the great mysteries of cinema has been solved by science.


Via JEB and NCBI.