Imprinting (ethology)
Lorenz showed how incubator-hatched geese would imprint on the first suitable moving stimulus they saw within what a 'critical period' of 13–16 hours after hatching. For example, the goslings would imprint on Lorenz himself (to be more specific, on his wading boots). He is often shown in photographs being followed by a gaggle of geese who had imprinted on him.