In psychology, imprinting is any type of rapid learning that occurs in a particular life stage. While this rapid learning is independent of the behavioral outcome, it also establishes it and can effect behavioral responses to different stimuli. Konrad Lorenz is well known for his classic studies of filial imprinting in graylag geese. From 1935 to 1938, he presented himself to a group of newly hatched gosling and took note of how he was instantly accepted, followed, and called to as if he were the one who laid them himself. As the first moving object they encountered, Lorenz studied the phenomenon in how quickly the geese were able to form such an irreversible bond. Through his work he demonstrated that this only developed during a brief “critical period,” which was about a few hours after hatching, suggesting a strong critical period.