Through the work of Lorenz, Hess
and others, imprinting research drew
wide attention. It shed light on many
important and controversial topics
of 1950s psychology, most notably
the problem of heredity and learning.
Hess took his work home with him,
raising chickens, geese, starlings, ducks,
hamsters, lambs and other animals at
his country home in Maryland. He and
his wife fed and cared for the animals,
and sometimes enlisted the help of
household appliances unintended for
such purposes. Their first gosling, for
example, was hatched in a makeshift
incubator that was ordinarily used as
a place for the rising of yeast dough.
By 1985, he and his wife had raised a
population of nearly 100 Canada geese.
Three Lions/Getty Images
Dr. eckhard Hess puts a rubber
helmet — with prisms in the
eyepieces — on a chick to test the
animal’s locating ability.
Imprinting, it seemed, was different
from most forms of learning. It appeared
A chick responds to a rubber ball as though it were its mother in Hess’s experiment.
the ball was the first object the chick saw after it hatched.
irreversible and confined to a critical
period, and seemed not to require
reinforcement. Later research suggested
that imprinting may in fact be reversible
and may extend beyond the critical
period identified by Lorenz and Hess.
Regardless, their findings helped to usher
in a new era of research on behaviors that
appeared to be genetically determined
Researchers continue to examine
imprinting as an example of tightly
constrained learning that involves
genetic predispositions. And, as the
Italian aviator Angelo d’Arrigo showed,
imprinting research has practical
applications for conserving endangered
species. Sadly, d’Arrigo died in 2006
while performing at an airshow in Sicily.
However, the practical applications
of imprinting continue to be used for
similar projects, including Operation
Migration, which is teaching captive-
born whooping cranes to follow small
aircrafts south for the winter. n
Cathy Faye is assistant director of the
Center for the History of Psychology at
the University of Akron. Katharine S.
Milar, PhD, is historical editor for “Time