Landsberg J W
J Comp Physiol Psychol. 1976 Jan;90(1):47-52. doi: 10.1037/h0077253.
Two experiments comparing developmental age and posthatch age were performed. In the first experiment 143 Peking ducklings of different posthatch ages were imprinted, and their following responses examined in a simultaneous choice test. A sensitive period was evident on the basis of posthatch age. In the second experiment 99 ducklings were separated in three clusters of different posthatch ages, which did not vary within the clusters relative to their probability to be imprinted. The ducklings of each cluster were imprinted at various developmental ages, and the results show the involvement of developmental age. Thus, both experiments considered together favor the concept of an interaction of developmental and posthatch age. Imprinting and the determination of the sensitive period are dependent on prehatch and posthatch learning, so both developmental age and posthatch age are involved in setting the limit of the sensitive period.
进行了两项比较发育年龄和孵化后年龄的实验。在第一个实验中，对143只不同孵化后年龄的北京鸭雏进行了印记，然后在同时选择测试中检查它们的跟随反应。基于孵化后年龄，一个敏感期是明显的。在第二个实验中，将99只鸭雏分成三群不同孵化后年龄的鸭雏，同一群内的鸭雏相对于被印记的概率没有差异。每一群的鸭雏在不同的发育年龄进行印记，结果表明发育年龄也起作用。因此，综合这两项实验支持发育年龄和孵化后年龄相互作用的概念。印记和敏感期的确定取决于孵化前和孵化后的学习，所以发育年龄和孵化后年龄都参与了设定敏感期的界限。
