Hoffman H S, Boskoff K J, Eiserer L A, Klein S H
J Comp Physiol Psychol. 1975 Jul;89(5):447-56. doi: 10.1037/h0077063.
Newly hatched Khaki Campbell ducklings (Anas platyrhynchos domesticus) were initially housed in pairs and subsequently transferred to isolated housing conditions. Subjects living with another bird displayed filial behavior and little aggression upon encountering another duckling in a test arena. In contrast, ducklings housed in isolation exhibited aggressive pecking in addition to filial behavior when another duckling was subsequently encountered. In Experiment 2, ducklings were housed with an imprinting object (i.e., an object that elicits attachment behavior), but they were otherwise isolated from other birds. These subjects displayed little aggression when they were subsequently reunited with a conspecific, indicating that the aggression-precluding effects of social housing are not limited to the particular social stimulus with which the ducklings are housed. In Experiment 3, ducklings were again housed with an imprinting object, but this time the object was behind glass, thereby precluding tactile contact with it. Since these birds also exhibited little aggression when reunited with a conspecific, it is apparent that visual stimulation from an imprinting object is sufficient in itself to preclude subsequent aggression. These findings suggest that stimulation that elicits attachment behavior is the critical factor mediating isolation-induced aggression.
刚孵化出的卡其坎贝尔鸭（家鸭）最初成对饲养，随后转移到隔离的饲养环境中。与另一只鸭子生活在一起的受试鸭表现出亲子行为，在测试场地遇到另一只小鸭时几乎没有攻击性。相比之下，隔离饲养的小鸭在随后遇到另一只小鸭时，除了亲子行为外还表现出攻击性啄咬。在实验2中，小鸭与一个印记对象（即引发依恋行为的对象）饲养在一起，但除此之外它们与其他鸭子隔离。这些受试鸭随后与同种个体重新团聚时几乎没有表现出攻击性，这表明群居的防攻击效果并不局限于小鸭所饲养的特定社会刺激物。在实验3中，小鸭再次与一个印记对象饲养在一起，但这次该对象在玻璃后面，从而排除了与它的触觉接触。由于这些鸭子在与同种个体重新团聚时也几乎没有表现出攻击性，显然来自印记对象的视觉刺激本身就足以防止随后的攻击。这些发现表明，引发依恋行为的刺激是介导隔离诱导攻击的关键因素。
