Douglas Spaulding is considered the father of modern ethology, which is the study of instinctive animal behavior (Goodwin, 2005). Spaulding began his research of animals in the 1860s in France. One of his early experiments involved “blindfolding” baby chickens before they had any visual experience outside an egg and then leaving them blindfolded for at least a few days. After removing the blindfolds the chicks were able to peck at moving insects naturally as if they had never been without sight. Spaulding stated that this was instinct, an in-born and inherent knowledge of basic survival skills. Other chicks were temporarily deafened at hatching time. When the material stopping up their ears was removed they were able to run towards a mother hen at the sound of a cluck. Again, Spaulding stated that this was an instinctual behavior. Spaulding also observed imprinting; he stated that baby chickens will follow any moving object if it was the first moving object that they saw.
Another ethological principle Spaulding proposed was critical periods. These are periods in which the development of a characteristic or attribute must develop. If it is delayed it will not fully develop. For example, if he stopped the hearing of chicks for too long (10 days or so) they would not respond to a call from a mother hen. If they were deprived of vision for too long they would not imprint and follow him. Developmental psychologists use the idea of critical periods (often called sensitive periods in humans) on which to base much research.