Definition
Imprinting is a special kind of learning. During a very short, special window just after birth, an animal locks the first thing it meets into its mind as its parent or mate, like pressing a stamp. Unlike ordinary studying or repeated training, a brief experience leaves a memory that stays for a long time and is hard to change.
Why does a newborn duckling follow people around?
You may have seen funny videos of ducklings waddling after a toy train or a person's heels. Birds like ducks and geese treat the first moving, noisy thing they see after hatching as their mother, no questions asked.
In nature, the real mother bird who sat on the eggs is always nearby. So for a chick, trusting the first moving thing in front of it is the safest, surest way to survive in a harsh wild world.
But if a researcher or a toy is there instead of the mother when the chick hatches, there's a problem. The chick firmly believes this strange new thing is its parent and follows it everywhere.
This is nothing like ordinary memory, which builds slowly through lots of practice. There's no reward and no training. A brief experience is enough to carve in a memory that rarely changes over time.
When the clock runs out, the brain's door closes
Imprinting isn't magic that can happen any time after birth. Every animal has a short window in time when this special memory can be stamped in. Biologists call it a sensitive period, or critical period.
In a classic experiment on mallard ducklings, the most sensitive time was 13 to 16 hours after hatching. If the duckling doesn't see a moving object during that time, imprinting doesn't happen easily later on, even when an object is shown.
On the other hand, once an object is chosen inside this window, it's very hard to switch to another one. It's like a footprint in wet cement: once it hardens, it's hard to wipe away.
So the door of memory swings wide and closes in a very short time, but once the stamp lands, it has strong staying power. Still, as Lorenz said, it's not always completely irreversible. Later studies suggest it can change under some conditions.
A little more precisely
Imprinting is not just a cute habit of following Mom. It's deeply tied to sexual imprinting, which shapes who an animal chooses as a mate when it grows up.
A bird imprinted on humans when young can be more drawn to people than to birds of its own species as an adult, and may even approach a person and perform a courtship dance. This is why, at wildlife centers, keepers who feed endangered bird chicks wear a hand puppet shaped like the mother bird.
Imprinting also works through smell and sound, not just sight. A classic example is the salmon. It imprints the unique smell of the water in the stream where it was born, then years later swims thousands of kilometers to return there and lay its eggs.
In the end, imprinting is a remarkable fact of life, created when instincts written in the genes meet the very first experiences after birth.
Common misconceptions
Imprinting means that at any time after birth, an animal automatically follows the first thing it sees.
It only happens during a set "critical period" early in life. After that window closes, imprinting doesn't easily happen, even if an object is shown.
Where you meet it
In a famous experiment, baby geese thought zoologist Konrad Lorenz was their mother and followed him in a line.
A crane raised by humans when young may perform a courtship dance for a person as an adult.
In one sentence
It's a kind of learning in which, during a short window early in life, an animal strongly stamps the first thing it sees as its parent or mate.