In psychology and ethology, imprinting is any kind of phase-sensitive learning
(learning occurring at a particular age or a particular life stage)
that is rapid and apparently independent of the consequences of
behaviour. It was first used to describe situations in which an animal
or person learns the characteristics of some stimulus, which is
therefore said to be "imprinted" onto the subject. Imprinting is
hypothesized to have a critical period.
Filial imprinting
The best-known form of imprinting is filial imprinting,
in which a young animal narrows its social preferences to an object
(typically a parent) as a result of exposure to that object. It is most
obvious in nidifugous birds, which imprint on their parents and then follow them around. It was first reported in domestic chickens, by Sir Thomas More in 1516 as described in his treatise Utopia, 350 earlier than by the 19th-century amateur biologist Douglas Spalding. It was rediscovered by the early ethologist Oskar Heinroth, and studied extensively and popularized by his disciple Konrad Lorenz working with greylag geese.
Lorenz demonstrated how incubator-hatched geese would imprint on
the first suitable moving stimulus they saw within what he called a "critical period"
between 13–16 hours shortly after hatching. For example, the goslings
would imprint on Lorenz himself (to be more specific, on his wading
boots), and he is often depicted being followed by a gaggle of geese
who had imprinted on him. Lorenz also found that the geese could
imprint on inanimate objects. In one notable experiment, they followed a
box placed on a model train in circles around the track. Filial imprinting is not restricted to non-human animals that are able to follow their parents, however.
The filial imprinting of birds was a primary technique used to create the movie Winged Migration (Le Peuple Migrateur),
which contains a great deal of footage of migratory birds in flight.
The birds imprinted on handlers, who wore yellow jackets and honked
horns constantly. The birds were then trained to fly along with a
variety of aircraft, primarily ultralights.
Imprinted geese and cranes flying with an ultralight aircraft
The Italian hang-glider pilot Angelo d'Arrigo extended this technique. D'Arrigo noted that the flight of a non-motorised hang-glider
is very similar to the flight patterns of migratory birds; both use
updrafts of hot air (thermal currents) to gain altitude that then
permits soaring flight over distance. He used this to reintroduce threatened species of raptors.
Because birds hatched in captivity have no mentor birds to teach them
traditional migratory routes, D'Arrigo hatched chicks under the wing of
his glider and imprinted on him. Then, he taught the fledglings to fly
and to hunt. The young birds followed him not only on the ground (as
with Lorenz) but also in the air as he took the path of various
migratory routes. He flew across the Sahara and over the Mediterranean Sea to Sicily with eagles, from Siberia to Iran (5,500 km) with a flock of Siberian cranes, and over Mount Everest with Nepalese eagles. In 2006, he worked with a condor in South America.
In a similar project, orphaned Canada geese were trained to their normal migration route by the Canadian ultralight enthusiast Bill Lishman, as shown in the fact-based movie drama Fly Away Home.
Chicks of domestic chickens
prefer to be near large groups of objects that they have imprinted on.
This behaviour was used to determine that very young chicks of a few
days old have rudimentary counting skills. In a series of experiments,
they were made to imprint on plastic balls and could figure out which of
two groups of balls hidden behind screens had the most balls.
American coot
mothers have the ability to recognize their chicks by imprinting on
cues from the first chick that hatches. This allows mothers to
distinguish their chicks from parasitic chicks.
The peregrine falcon
has also been known to imprint on specific structures for their
breeding grounds such as cliff sides and bridges and thus will favour
that location for breeding.
Sexual imprinting
Sexual imprinting is the process by which a young animal learns the characteristics of a desirable mate. For example, male zebra finches
appear to prefer mates with the appearance of the female bird that
rears them, rather than that of the birth parent when they are
different.
Sexual attraction to humans can develop in non-human mammals or
birds as a result of sexual imprinting when reared from young by humans.
One example is London Zoo female giant panda Chi Chi. When taken to Moscow Zoo for mating with the male giant panda An An, she refused his attempts to mate with her, but made a full sexual self-presentation to a zookeeper.
It commonly occurs in falconry
birds reared from hatching by humans. Such birds are called "imprints"
in falconry. When an imprint must be bred from, the breeder lets the
male bird copulate with their head while they are wearing a special hat
with pockets on to catch the male bird's semen. The breeder then courts a suitable imprint female bird (including offering food, if it is part of that species's normal courtship).
At "copulation," the breeder puts the flat of one hand on the female
bird's back to represent the weight of a male bird, and with the other
hand uses a pipette, or a hypodermic syringe without a needle, to squirt the semen into the female's cloaca.
Sexual imprinting on inanimate objects is a popular theory concerning the development of sexual fetishism. For example, according to this theory, imprinting on shoes or boots (as with Konrad Lorenz's geese) would be the cause of shoe fetishism.
Limbic imprinting
Some suggest that prenatal, perinatal and post-natal experiences leave imprints upon the limbic system, causing lifelong effects and this process is identified as limbic imprinting.
The term is also described as the human emotional map, deep-seated
beliefs, and values that are stored in the brain's limbic system and
govern people's lives at the subconscious level.
It is one of the suggested explanations for the claim that the
experiences of an infant, particularly during the first two years of his
life, contribute to his lifelong psychological development.
Imprinted genes can have astounding effects on body size, brain size,
and the process in which the brain organizes its processes. Evolutionary
trends within the animal kingdom have been shown to show substantive
increase in the fore-brain particularly towards the limbic system, this evolution has even been through of to have a mutative effect on the brain size trickling down the human ancestry.
Westermarck effect
Reverse sexual imprinting is also seen in instances where two
people who live in domestic proximity during the first few years in the
life of either one become desensitized to later close sexual attraction. This phenomenon, known as the Westermarck effect, was first formally described by Finnish anthropologist Edvard Westermarck in his book The History of Human Marriage (1891). The Westermarck effect has since been observed in many places and cultures, including in the Israeli kibbutz system, and the Chinese shim-pua marriage customs, as well as in biological-related families.
In the case of the Israeli kibbutzim (collective farms), children
were reared somewhat communally in peer groups, based on age, not
biological relation. A study of the marriage patterns of these children
later in life revealed that out of the nearly 3,000 marriages that
occurred across the kibbutz system, only fourteen were between children
from the same peer group. Of those fourteen, none had been reared
together during the first six years of life. This result provides
evidence not only that the Westermarck effect is demonstrable but that
it operates during the period from birth to the age of six. However, Eran Shor and Dalit Simchai claimed that the case of the kibbutzim actually provides little support for the Westermarck effect.
When proximity during this critical period
does not occur—for example, where a brother and sister are brought up
separately, never meeting one another—they may find one another highly
sexually attractive when they meet as adults. This phenomenon is known as genetic sexual attraction. This observation supports the hypothesis that the Westermarck effect evolved because it suppressed inbreeding. This attraction may also be seen with cousin couples.
Sigmund Freud
argued that as children, members of the same family naturally lust for
one another, making it necessary for societies to create incest taboos, but Westermarck argued the reverse, that the taboos themselves arise naturally as products of innate attitudes. Steven Pinker
has written that Freud's conception of an urge to incest may have
derived from Freud's own erotic reaction to his mother as a boy
(attested in Freud's own writings), and speculates that Freud's reaction
may have been due to lack of intimacy with his mother in early
childhood, as Freud was wet-nursed.
Baby duck syndrome
Ducklings following their mother.
In human–computer interaction, baby duck syndrome
denotes the tendency for computer users to "imprint" on the first
system they learn, then judge other systems by their similarity to that
first system. The result is that "users generally prefer systems similar to those they learned on and dislike unfamiliar systems".
The issue may present itself relatively early in a computer user's
experience, and it has been observed to impede education of students in
new software systems or user interfaces.
