Mind, Body, World- Foundations of Cognitive Science, 2013a

physical robot that acts like a Braitenberg vehicle (Dawson, Dupuis, & Wilson, 2010)
is embodied. The physical structure of the robot itself is important in the sense
that it is a source of behavioural complexity. Computer simulations of Braitenberg
vehicles are idealizations in which all motors and sensors work perfectly. This is
impossible in a physically realized robot. In an embodied agent, one motor will be
less powerful than another, or one sensor may be less effective than another. Such
differences will alter robot behaviour. These imperfections are another important
source of behavioural complexity, but are absent when such vehicles are created in
simulated and idealized worlds.
However, embodiment is more complicated than mere physical existence.
Physically existing agents can be embodied to different degrees (Fong, Nourbakh
sh, & Dautenhahn, 2003). This is because some definitions of embodiment relate
to the extent to which an agent can alter its environment. For instance, Fong,
Nourbakhsh, & Dautenhahn (2003, p. 149) argued that “embodiment is grounded in
the relationship between a system and its environment. The more a robot can perturb
an environment, and be perturbed by it, the more it is embodied.” As a result,
not all robots are equally embodied (Dawson, Dupuis, & Wilson, 2010). A robot that
is more strongly embodied than another is a robot that is more capable of affecting,
and being affected by, its environment.
The power of embodied cognitive science emerges from agents that are both
situated and embodied. This is because these two characteristics provide a critical
source of nonlinearity called feedback (Ashby, 1956; Wiener, 1948). Feedback occurs
when information about an action’s effect on the world is used to inform the progress
of that action. As Ashby (1956, p. 53) noted, “‘feedback’ exists between two
parts when each affects the other,” when “circularity of action exists between the
parts of a dynamic system.”
Wiener (1948) realized that feedback was central to a core of problems involving
communication, control, and statistical mechanics, and that it was crucial to
both biological agents and artificial systems. He provided a mathematical framework
for studying communication and control, defining the discipline that he called
cybernetics. The term cybernetics was derived from the Greek word for “steersman”
or “governor.” “In choosing this term, we wish to recognize that the first significant
paper on feedback mechanisms is an article on governors, which was published by
Clerk Maxwell in 1868” (Wiener, 1948, p. 11). Interestingly, engine governors make
frequent appearances in formal discussions of the embodied approach (Clark, 1997;
Port & van Gelder, 1995b; Shapiro, 2011).
The problem with the nonlinearity produced by feedback is that it makes computational
analyses extraordinarily difficult. This is because the mathematics of
feedback relationships between even small numbers of components is essentially
Elements of Embodied Cognitive Science 217