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. Lorenz also discovered a long-lasting effect of his studies, and that was a shift in the species' sexual imprinting as a result from imprinting upon a foster mother of a second species. For certain species, when raised by a second one, they develop and retain imprinted preferences and approach the second species they were raised by rather than choose their own, if given a choice. Imprinting serves as the distinguishing factor between one's own mother and other mother figures. The mother and the infant both identify with each other, this is a strong bonding moment for humans. It provides a sort of model or guide to adult behaviors in addition to other factors such as nurture, protection in infancy, guidance, and nourishment. The imprinting process, Lorenz also found, brought about a sense of familiarity for the young animals. When such a strong bond is formed at such an early stage, it creates a sense of security and comfort for the subject and actually encourages the imprinting behavior. Pheromones play a key role in the imprinting process, they trigger a biochemical response in the recipient, leading to a confirmed identification in the other individual. If direct contact between mother and infant is not maintained during the critical imprinting period, then the mother goose may reject the infant because she is unfamiliar with her newborn's scent. If that does happen, then the infant's life would be in jeopardy unless it were claimed by a substitute mother, possibly leading to awkward social behavior in later life. In relation to humans, a newborn during the critical period identifies with its mother's and other peoples' scents since its scent is one of the most developed senses at that stage in life. The newborn uses this pheromone identification to seek the people it identifies with, when in times of distress, hunger, and discomfort as a survival skill. Inferences could be made for newborns based upon Lorenz's studies. When imprinting on their mothers, newborns look to them for nourishment, a sense of security, and comfort. Human