Imprinting is a form of animal learning which occurs at a very specific stage in that animal's life. Imprinting can take a variety of forms, but the most famous type of imprinting is probably filial imprinting, in which young birds learn to recognize and follow their parents. Typically, in addition to being time-sensitive, imprinting also happens very quickly, with animals quickly absorbing the lessons they need to learn.

In addition to being famous, filial imprinting is also an excellent and easy to understand type of imprinting. When young birds such as geese, chickens, and ducks hatch, they are predisposed to form a strong attachment with the first object they see, which is generally a parent, most typically the mother. As a result, the young birds will follow the mother around, learning to recognize other members of their species and picking up various important life skills, from swimming to looking for food.

In the 1930s, a researcher named Konrad Lorenz became very interested in imprinting, and he managed to prove that geese and ducks really will become attached to the first moving thing they see, whether or not it is another duck. He managed to raise a flock of geese which imprinted on him, and numerous charming photographs of Lorenz followed by a gaggle of geese can be seen in various publications on imprinting to testify to his success.

Biologists who raise young birds with the intent of releasing them back into the wild tend to be very careful around their charges, as they do not want their birds to imprint on them. Instead, puppets designed to resemble adult birds are used to feed and interact with the chicks, encouraging a more natural form of imprinting which will give the birds a better chance at survival after release.

Many people believe that imprinting is very important to social development. Young birds deprived of a chance to imprint are often socially awkward, and they may not recognize other members of their species, or they may have difficulty engaging in basic behaviors which are common to their species. Imprinting also appears to play a role in sexual attraction and other responses to members of the same species.

In an interesting phenomenon known as reverse imprinting or the Westermarck Effect, researchers have found that people who spend the early years of childhood together tend to be less prone to sexual attraction to each other. This could be viewed as a form of desensitization, and it has been documented in several societies, suggesting that it is a genuine psychological phenomenon, rather than a cultural one.