Konrad Lorenz (1903–1989) was an Austrian zoologist who discovered imprinting, the process by which young animals form a lasting attachment to the first moving object they see after birth.
His experiments with geese and ducks showed that this attachment forms automatically within a brief critical period and does not depend on feeding.
The finding suggested that early social bonds can be innate, and it later shaped psychologist John Bowlby’s theory of human attachment.
Key Takeaways
- Imprinting: Goslings and ducklings form an attachment to the first large moving object they see after hatching, without needing to be fed.
- Critical Period: Hess (1958) found imprinting was strongest between 12 and 17 hours after hatching and rare after 32 hours.
- Reversibility: Guiton (1966) and Sluckin (1965) showed imprinting is not fully fixed; later contact with an animal’s own species can partly reverse it.
- Attachment Theory: Lorenz’s non-feeding evidence helped psychologist John Bowlby argue that human attachment is innate rather than based on feeding.
- Nobel Prize: Lorenz shared the 1973 Nobel Prize in Physiology or Medicine with Tinbergen and von Frisch for founding ethology.
This process suggests that attachment is innate and programmed genetically.
Psychologist John Bowlby later drew directly on this finding. Lorenz’s goslings formed their attachment without any feeding taking place.
This challenged learning-theory accounts of the mother-infant bond, sometimes called ‘cupboard love’ theory, which held that infants attach to whoever feeds them. Bowlby (1969) argued instead that attachment evolves as an innate behavioural system.
He took a large clutch of goose eggs and kept them until they were about to hatch. Half of the eggs were then placed under a goose mother, while Lorenz kept the other half in an incubator.
He made sure he was the first moving object the newly hatched goslings encountered.
When the geese hatched Lorenz imitated a mother duck’s quacking sound, upon which the young birds regarded him as their mother and followed him accordingly. The other group followed the mother goose.
This following response is what Lorenz called imprinting.
Lorenz believed that once imprinting has occurred, it cannot be reversed, nor can a gosling imprint on anything else.
To ensure imprinting had occurred, Lorenz put all the goslings together under an upturned box and allowed them to mix. When the box was removed, the two groups separated to go to their respective “mothers” – half to the goose, and half to Lorenz.
For example, Guiton (1966) used yellow rubber gloves to feed chicks during the critical period, and the chicks imprinted on the glove.
This suggests that young animals imprint on any moving object present during the critical period of development. The chicks were later found trying to mate with the yellow rubber glove.
This corroborated Lorenz’s original findings: the chicks’ preference for the glove persisted into adulthood, producing a lasting change in social and sexual behaviour that Guiton (1966) called sexual imprinting.
Imprinting does not appear to be active immediately after hatching, although there seems to be a critical period during which imprinting can occur.
Hess (1958) showed that the imprinting process could occur as early as one hour after hatching. The strongest responses occurred between 12 and 17 hours, and the response was unlikely to occur at all after 32 hours. Like Lorenz, Hess believed the preference was permanent.
Imprinting has consequences, both for short-term survival, and in the longer term forming internal templates for later relationships. Imprinting occurs without any feeding taking place.
However, Lorenz’s claim that imprinting produces a permanent, irreversible change in the nervous system has since been criticised.
Guiton (1966) found that after chicks spent time with their own species, they could still engage in normal sexual behaviour, suggesting imprinting is only moderately reversible. Klein, Hoffman, and DePaulo (1976) reported a similar reversal in ducklings.
Critical Evaluation
The imprinting phenomenon itself has been replicated many times since Lorenz’s original demonstration. Parts of his wider theoretical framework have not survived as well.
From Critical Period to Sensitive Period
Lorenz originally described a strict critical period. Outside this narrow window, he believed imprinting could not occur at all, and a formed preference could never be reversed.
Guiton’s (1966) glove-reared chicks challenged that picture directly. Wladyslaw Sluckin (1965) then reviewed a decade of imprinting research in his book Imprinting and Early Learning.
Sluckin proposed a new idea: the sensitive period.
This is a stage when the relevant learning is most likely and easiest, but not strictly switched on or off. Under this model, learning can still occur outside the sensitive window, only slower and less complete.
This softer framework fit the evidence on reversibility and on unusual imprinting ages far better than Lorenz’s original version.
This concept is now standard. It spans vision, hearing, birdsong, and language research, and John Bowlby adopted the same term for the human attachment window.
The Hydraulic Model of Motivation
Lorenz also proposed that instinctive behaviour was driven by a build-up of action-specific energy. On this model, energy accumulated within the animal and discharged once the right stimulus appeared, much like water held back by a valve.
The model was already disputed during Lorenz’s own lifetime. Robert Hinde (1960, 1970) showed that the physiological evidence did not support a literal energy build-up.
Mainstream ethology has since dropped the idea.
The hydraulic picture is no longer treated as an adequate account of motivation. The same energy model underpinned Lorenz’s popular book On Aggression (1966), which argued that human violence builds up inside us and needs periodic release.
Scientific reviewers rejected the human generalisation. S. A. Barnett (1967) called it unsupported by evidence, and Erich Fromm (1973) mounted a book-length critique from a broader biosocial standpoint.
Contemporary Research
Modern research has moved from behaviour to the brain. Brian McCabe’s review of the field (McCabe, 2019) describes how visual imprinting in young chicks is now understood as a well-defined form of learning.
It centres on one forebrain region, the intermediate medial mesopallium (IMM). The region is tiny but critical.
Exposure to an imprinting stimulus produces measurable structural and chemical changes inside the IMM.
Removing the IMM abolishes these preferences. Other kinds of learning stay intact.
Johan Bolhuis and Robert Honey (1998) had earlier brought the behavioural and neurobiological evidence together to make the same case. Together, this research confirms that the imprinting effect Lorenz described in 1935 is real and repeatable.
It replaces his hydraulic-energy explanation with a detailed account grounded in identified brain circuits.
Who Was Konrad Lorenz?
Konrad Zacharias Lorenz was born in Vienna on 7 November 1903, the son of surgeon Adolf Lorenz. He grew up at the family’s estate in Altenberg, on the Danube, where he kept and observed animals from childhood.
Early Life and the Founding of Ethology
Lorenz’s father steered him toward medicine. He studied briefly at Columbia University in New York in 1922, then returned to Vienna and qualified in medicine from the University of Vienna in 1928.
He also read for a doctorate in zoology, submitting a thesis on the comparative behaviour of crows and their relatives, and was awarded his PhD in 1933.
Between 1927 and 1937, working largely without institutional support, Lorenz carried out his classic fieldwork on jackdaws, geese, and ducks at Altenberg. He published prolifically in the Journal für Ornithologie.
In 1936 he met fellow zoologist Nikolaas Tinbergen, and hosted him at Altenberg the following year. Together they laid the foundations of ethology, the biological study of animal behaviour under natural conditions.
The Nazi Period
In 1938, after Austria’s annexation, Lorenz joined the Nazi Party. In 1940 he took up a chair at the University of Königsberg with the party’s backing.
The chair once belonged to Immanuel Kant.
A 1940 paper by Lorenz applied his ideas about animal ‘degeneration’ to human society, arguing for a programme of racial hygiene. Historians treat this as a genuine and troubling part of his record (Deichmann, 1996; Sax, 1997).
He served as a German army psychiatrist during the war. He then spent nearly four years as a prisoner of war in the Soviet Union.
After the war, Lorenz called his party membership a serious error of judgement, though historians note he never fully retracted the 1940 paper’s arguments.
The University of Salzburg revoked an honorary doctorate it had given him, citing this history, in 2015.
Later Career and the Nobel Prize
Lorenz returned to a defeated Austria in 1948. No academic post was open to a man with his political record, so he worked for a time from Altenberg on a small grant.
Help arrived in 1950.
The Max Planck Society, through the efforts of Erich von Holst, established a research station for him at Buldern in Westphalia. It was reconstituted in 1961 as the Max Planck Institute for Behavioural Physiology at Seewiesen, in Bavaria, with Lorenz as founding co-director.
The Seewiesen years were the summit of his career.
In 1973 he shared the Nobel Prize in Physiology or Medicine with Nikolaas Tinbergen and Karl von Frisch for establishing ethology as a science. Lorenz retired from Seewiesen that same year and returned to Altenberg.
Altenberg welcomed him back.
The Austrian Academy of Sciences opened a department for animal sociology to house his work. He continued studying his greylag geese at the Konrad-Lorenz-Forschungsstelle in Grünau im Almtal, which he founded in 1973.
He died at Altenberg on 27 February 1989, aged 85.
References
Barnett, S. A. (1967). Review of On Aggression by Konrad Lorenz. Scientific American, 216(2), 135–138.
Bolhuis, J. J., & Honey, R. C. (1998). Imprinting, learning and development: From behaviour to brain and back. Trends in Neurosciences, 21(7), 306–311. https://doi.org/10.1016/S0166-2236(98)01258-2
Bowlby, J. (1969). Attachment and loss. Vol. 1: Attachment. Hogarth Press.
Deichmann, U. (1996). Biologists under Hitler. Harvard University Press.
Fromm, E. (1973). The anatomy of human destructiveness. Holt, Rinehart & Winston.
Guiton, P. (1966). Early experience and sexual object-choice in the brown leghorn. Animal Behaviour, 14(4), 534–538. https://doi.org/10.1016/S0003-3472(66)80056-8
Hess, E. H. (1958). Imprinting in animals. Scientific American, 198(3), 81-90.
Hinde, R. A. (1960). Energy models of motivation. Symposia of the Society for Experimental Biology, 14, 199–213.
Hinde, R. A. (1970). Animal behaviour: A synthesis of ethology and comparative psychology (2nd ed.). McGraw-Hill.
Klein, S. H., Hoffman, H. S., & DePaulo, P. (1976). Some effects of early social stimulation on the emotional reactivity of ducklings. Animal Learning & Behavior, 4(3), 257-260.
Lorenz, K. (1935). Der Kumpan in der Umwelt des Vogels. Der Artgenosse als auslösendes Moment sozialer Verhaltensweisen. Journal für Ornithologie, 83, 137–215, 289–413. https://doi.org/10.1007/BF01905355
McCabe, B. J. (2019). Visual imprinting in birds: Behavior, models, and neural mechanisms. Frontiers in Physiology, 10, 658. https://doi.org/10.3389/fphys.2019.00658
Sax, B. (1997). What is a “Jewish dog”? Konrad Lorenz and the cult of wildness. Society & Animals, 5(1), 3–21. https://doi.org/10.1163/156853097X00196
Sluckin, W. (1965). Imprinting and early learning. Aldine.
