Read Online Animals in Translation by Temple Grandin - Free Book Online Page B
Authors: Temple Grandin
Ads: Link
high-contrast images, like a shiny reflection on metal, or a sparkling reflection in a puddle. Several of the other visual distracters, such as a white Styrofoam or plastic coffee cup on the floor or a piece of clothing hanging over a fence, involve contrast, too. I have some photographs of high-contrast distracters on my Web site. One is a picture of a white coffee cup on a brown floor; another is a pair of bright yellow boots against a gray floor and railing.
Sharp contrasts are also a problem when youâre trying to move an animal toward an area thatâs either too dark or too light. We already talked about the cattle that wouldnât go into the squeeze chute building because it was too dark, but cattle will also refuse to walk directly into an area that is too bright. Strong changes in light are so distracting to cattle that you canât have direct sources of lighting, like an unshaded lantern or lightbulb, at the mouth of an alley. They wonât walk toward it. You want overhead lighting withno shadows, like the light outdoors on a bright but cloudy day. Sometimes you can get that effect with skylights made out of white translucent plastic.
Slowly rotating fan blades are also a high-contrast stimulus, because animals see contrast differently from the way we do. If the fan is turned on and is rotating so fast you canât see the blades, thereâs no problem. But when a fan blade is turning slowly it creates a flicker, and that flicker is a much higher contrast image for an animal than it is for us.
Animals see more intense contrasts of light and dark because their night vision is so much better than ours. Good night vision involves excellent vision for contrasts and relatively poor color vision. I first learned about animalsâ incredible contrast vision back when I was taking black-and-white pictures of the cattle chutes. Thereâd be a shadow on the ground that even I wouldnât see until I got the pictures developed. The reason I could see it only in my photographs is that contrast is much sharper when you take away color. Shadows are so much clearer in black and white that during World War II the Allies recruited people who were completely color-blindânot just red-green color-blind, but people who didnât see any color at allâto interpret reconnaissance and spy photos. They could spot things like netting draped over a tank to camouflage it that were invisible to people whose color vision was normal.
Animals seem to see sharp contrast on the floor as a false visual cliff; they act as if they think the dark spots are deeper than the lighter spots. Thatâs why cattle guards work on roads. A cattle guard is a pit dug across a road, covered with metal bars. A car can drive over it and a cow could walk over it if it tried, but it wonât because it sees the two-foot drop-off between the bars.
To a cow the contrast is so sharp the drop-off probably looks like a bottomless pit. In An Anthropologist on Mars Oliver Sacks has an essay about an artist who lost his color vision in a car crash. After that it was hard for him to drive, because tree shadows on the road looked like pits his car could fall into. Without color vision, he saw contrasts between light and dark as contrasts in depth. 3 Since cows have much poorer color vision than normal people do and mainly see colors in the yellow-green range, they may see light-dark contrasts as contrasts in depth in an analogous fashion to Dr. Sacksâs color-blind artist.
Whatever the reason, cows act like Dr. Sacksâs color-blind artist. Cattle guards are expensive to build, so a lot of times the Department of Transportation just uses a standard line-painting machine (thatâs the machine they use to paint the center line on highways) to paint batches of bright white lines across the highway going in the same direction as a crosswalk. Itâs a poor manâs cattle guard.
When the cattle arenât highly motivated
Sharp contrasts are also a problem when youâre trying to move an animal toward an area thatâs either too dark or too light. We already talked about the cattle that wouldnât go into the squeeze chute building because it was too dark, but cattle will also refuse to walk directly into an area that is too bright. Strong changes in light are so distracting to cattle that you canât have direct sources of lighting, like an unshaded lantern or lightbulb, at the mouth of an alley. They wonât walk toward it. You want overhead lighting withno shadows, like the light outdoors on a bright but cloudy day. Sometimes you can get that effect with skylights made out of white translucent plastic.
Slowly rotating fan blades are also a high-contrast stimulus, because animals see contrast differently from the way we do. If the fan is turned on and is rotating so fast you canât see the blades, thereâs no problem. But when a fan blade is turning slowly it creates a flicker, and that flicker is a much higher contrast image for an animal than it is for us.
Animals see more intense contrasts of light and dark because their night vision is so much better than ours. Good night vision involves excellent vision for contrasts and relatively poor color vision. I first learned about animalsâ incredible contrast vision back when I was taking black-and-white pictures of the cattle chutes. Thereâd be a shadow on the ground that even I wouldnât see until I got the pictures developed. The reason I could see it only in my photographs is that contrast is much sharper when you take away color. Shadows are so much clearer in black and white that during World War II the Allies recruited people who were completely color-blindânot just red-green color-blind, but people who didnât see any color at allâto interpret reconnaissance and spy photos. They could spot things like netting draped over a tank to camouflage it that were invisible to people whose color vision was normal.
Animals seem to see sharp contrast on the floor as a false visual cliff; they act as if they think the dark spots are deeper than the lighter spots. Thatâs why cattle guards work on roads. A cattle guard is a pit dug across a road, covered with metal bars. A car can drive over it and a cow could walk over it if it tried, but it wonât because it sees the two-foot drop-off between the bars.
To a cow the contrast is so sharp the drop-off probably looks like a bottomless pit. In An Anthropologist on Mars Oliver Sacks has an essay about an artist who lost his color vision in a car crash. After that it was hard for him to drive, because tree shadows on the road looked like pits his car could fall into. Without color vision, he saw contrasts between light and dark as contrasts in depth. 3 Since cows have much poorer color vision than normal people do and mainly see colors in the yellow-green range, they may see light-dark contrasts as contrasts in depth in an analogous fashion to Dr. Sacksâs color-blind artist.
Whatever the reason, cows act like Dr. Sacksâs color-blind artist. Cattle guards are expensive to build, so a lot of times the Department of Transportation just uses a standard line-painting machine (thatâs the machine they use to paint the center line on highways) to paint batches of bright white lines across the highway going in the same direction as a crosswalk. Itâs a poor manâs cattle guard.
When the cattle arenât highly motivated
Similar Books
