Lorenz and Tinbergen reported differences in their experiments with Lorenz arguing that a short neck only elicits a flight response in turkeys, while Tinbergen claimed: “The reactions of young gallinaceous birds, ducks, and geese to a flying bird of prey are released by the sign-stimulus ‘short neck’ among others”. Konrad Lorenz and Nikolaas Tinbergen worked together in 1937 on experiments that were each published separately in 1939. This provoked Konrad Lorenz's and Nikolaas Tinbergen's to design and explore the Hawk/Goose effect. Tinbergen, in 1951, pointed out that he was inspired by Oscar Heinroth's observations in which he stated that domestic chickens are more alarmed by short necked birds, over long necks ones. He found that naive Capercaillie exhibited a greater fear response to a silhouette of a hawk than to a circle, a triangle, or a generalized bird silhouette, but that this varied with both species, and prior experience. Innate or learned behaviour Ī Brief History Pointing to Innate Behaviorįriedrich Goethe was the first to perform experiments using silhouettes (1937, 1940). The perceived identity influences how the figure is perceived to move, such that the figure is assumed to be a hawk or a goose based on the movement in direction of the head and the protrusion of the wings (short on one end and a long one on the other). When moving the figure in one direction, it represents a shape resembling a hawk (short neck long tail) while moving the figure in the opposite direction resembles a goose (long neck short tail).
Just like what is seen in Tinbergen’s 1951 experiment the same figure is used to represent both the hawk and the goose in most hawk/goose experiments. Hawk or goose distinguished by direction of movement 1 Hawk or goose distinguished by direction of movement.Initially thought to be an inborn instinct developed from natural selection, it was subsequently shown by others to be socially reinforced by other birds. A study later confirmed that perception of an object was influenced by the direction of motion because the object in question was considered to be moving forwards in that direction. Later Tinbergen reported that a single shape that was sort of an abstract composite of the hawk and goose silhouettes could produce the effect if moved in one direction but not the other. Goose-like shapes were ignored while hawk-like shapes produced the response. Moving it from right to left (in the direction of dashed arrow) produced no response, but moving it from left to right (in the direction of solid arrow) elicited the behavior.Īs part of their introducing experimentalism into animal behavior research they performed experiments in which they made 2-dimensional silhouettes of various bird-like shapes and moved them across the young birds' line of vision. One of the goose/hawk models as reported by Tinbergen.
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