Dogs are not color blind in the true sense

It turns out that dogs are color blind This statement is not entirely accurate, because dogs are not unable to distinguish all colors, but their ability to distinguish different colors is relatively poor. They can still distinguish other colors well. To determine whether a person is color blind, we only need to ask people to distinguish a few simple numbers or images from a colorful array. So how did researchers obtain the idea that dogs are color blind? Of.

The so-called color blindness means that you can only see part of the incoming light spectrum, so there are certain restrictions on the inference of color. However, this does not prove that dogs’ judgment of colors is very simple. In other words, dogs can still distinguish many different colors. Researchers have used many experiments to prove this idea.

There are two types of cone cells in the dog's retina. They can distinguish between short wavelength and medium and long wavelength light waves, that is, they can experience blue light (wavelength). light waves) and red and yellow light (medium and long wavelength light waves). Due to the small number of cones, the colors in the world in dogs' eyes are not as colorful as what we see. However, humans have three types of cones that allow us to see all colors of light in the spectrum. Because dogs only have two types of cones, the colors they can distinguish are the same as those of red-green color blindness patients. However, color blind patients can also see many other different colors, so can dogs also see these colors? Scientists have used two methods to determine this.

Dogs can also distinguish blue, purple and other related colors

One ​​way is to shine a beam of colored light into the dog's eyes, so that an image is reflected directly back from the dog's eyes. ScienceThe scientists studied this reflected image and then compared it with the image of the same kind of light reflected back through the human eye.

Another approach is that trained dogs can "tell" scientists what they see in the world. In the experiment, the scientists successively gave the dogs a set of emotions. Each group had three emotions, two of which were normal. And with a little training, the dogs would use their noses to point out to the scientists the light of the distinctive expression in each group. Scientists only need to keep changing the color of the light and repeat this process to conclude that the world is black in the eyes of dogs. White and dark gray, mixed with medium- and long-wavelength red-yellow light and short-wavelength blue light, make the world look like pictures on a black and white TV. Only the brightness of the black holes is different, but the changes in color cannot be distinguished. The reason why guide dogs can distinguish traffic lights is based on the brightness of the two lights. Dogs have a very fine ability to distinguish between shades of gray. With this ability, they can distinguish changes in light and shade on objects and create a three-dimensional visual image.

Dogs have a better ability to distinguish colors such as black, white and gray. In addition, dogs can also distinguish different shades of blue, Indigo and purple, from this point of view, dogs are not completely color blind as we say, but their ability to distinguish certain colors is relatively weak, so dogs can still distinguish more colors. of.

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