Tutorial on Embodiment
3.1. Theoretical Scheme
In what follows, we will illustrate the concept of embodiment with the help of various case studies on biological (humans and animals) as well as artificial agents (robots). To give a better overview to the reader, we will use one theoretical scheme (Fig. 3.1.1) throughout the chapter and locate all the case studies on it.
Fig. 3.1.1. A theoretical scheme illustrating different components whose interaction comprises an agent's embodiment (Pfeifer et al. 2007)
First, let us briefly comment on some of the components that can be seen in Fig. 3.1.1.
Motor commands are the instructions generated by the central nervous system in an animal or by a controller in the case of a robot. They are sent to the agent's actuators: muscles or motors.
Mechanical feedback describes the reaction that the agent's mechanical system experiences after acting on the environment. This can be pressure on the bones, torques in the joints, or passive deformations of skin tissue, for instance.
External physical stimulation refers to the effects of the environment on the agent's sensory system. This is of course dependent on the sensors that are available to the agent. The stimuli can include pressure, temperature, or electromagnetic fields.
Internal physical stimuli refer to forces and torques developed in the muscles and joint-supporting ligaments, as well as accelerations to sensory receptors in the mechanical system.
The agent is embedded in a task-environment/ecological niche. This encompasses all forces such as gravity and friction that act on the agent.