  Information-theoretic fitness functions are becoming increasingly popular to
produce generally useful, task-independent behaviors. One such universal
function, dubbed empowerment, measures the amount of control an agent exerts on
its environment via its sensorimotor system. Specifically, empowerment attempts
to maximize the mutual information between an agent's actions and its received
sensor states at a later point in time. Traditionally, empowerment has been
applied to a conventional sensorimotor apparatus, such as a robot. Here, we
expand the approach to a distributed, multi-agent sensorimotor system embodied
by a neural cellular automaton (NCA). We show that the addition of empowerment
as a secondary objective in the evolution of NCA to perform the task of
morphogenesis, growing and maintaining a pre-specified shape, results in higher
fitness compared to evolving for morphogenesis alone. Results suggest there may
be a synergistic relationship between morphogenesis and empowerment. That is,
indirectly selecting for coordination between neighboring cells over the
duration of development is beneficial to the developmental process itself. Such
a finding may have applications in developmental biology by providing potential
mechanisms of communication between cells during growth from a single cell to a
multicellular, target morphology. Source code for the experiments in this paper
can be found at: \url{https://github.com/caitlingrasso/empowered-nca}.
