Motion Studies of human imitation

The Ethology of Animal Imitation

To be able to recognize and reproduce others' actions is a powerful means of learning and developing new skills. However, there is still some debate over what behaviors the term "imitation" refers to and in which species it is exhibited. For ethologists, animal imitation is best described in terms of levels of complexity.

"True" imitation would be the ability to replicate and by so doing learn skills which are not part of the animal's prior repertoire by observation of those performed by others.

Only humans and possibly great apes would be capable of True Imitation. Other species' capabilities would be described as social facilitation, copying and mimicry.

Human Imitation

Imitation is fundamental to human interactions and appear early in the child's development. From the very first months, the child is capable of imitating facial expressions (protusing the tongue) and gestural expressions (from kicking a ball to manipulating objects).

However, some patients suffering from cerebral lesions show an abnormal imitative behavior. They are either incapable of imitating or interpreting others' motion (apraxia). Or, conversely, they are incapable of preventing themselves from imitative (obsessive or compulsory imitation). Similar deficits in the ability to imitate can be observed in children with autism or with Down syndrome.

What are the neural processes at the basis of our ability to imitate?
Can we take inspiration from behavioral and neurological studies of imitation in children and adults to better understand these processes?

Kinematics recordings of human motion

We investigate the mechanisms by which humans learn rapidly new motor skills by the observation and replication of a demonstration. This investigation is done through a detailed analysis of data from human motion kinematics during different imitation tasks. 

Stimuli for the experiments are produced using a computer generated human model (an avatar). Subjects are requested to reproduce the movement displayed by the avatar. We use 3D motion capture systems, which allow fast and accurate measurement of the movement of ten segments of the body, which allows reconstruction of the whole body motion.

Research:

	Normal Imitation
	Apraxia