ABSTRACT
An individual, under stimulation, is able to take different attitudes corresponding to the external excitants. A child who sees a pretty coloured butterfly, tries to catch it as it flies by. If a toad jumps near him, he avoids it with disgust. If he sees the grass move just beside him, he stops and tries to discover what caused the movement, ready to flee if it is a snake, or, if it is a wounded bird, prompt to pick it up.
