9.3. Embodied Communication 163 9.3 Embodied Communication Next we turn to the potential cognitive implications of seeking to achieve goals in an environ- ment in which multimodal communication with other agents plays a prominent role. Consider a community of embodied agents living in a shared world, and suppose that the agents can communicate with each other via a set of mechanisms including: e Linguistic communication, in a language whose semantics is largely (not necessarily wholly) interpretable based on the mutually experienced world e Indicative communication, in which e.g. one agent points to some part of the world or delimits some interval of time, and another agent is able to interpret the meaning e Demonstrative communication, in which an agent carries out a set of actions in the world, and the other agent is able to imitate these actions, or instruct another agent as to how to imitate these actions e Depictive communication, in which an agent creates some sort of (visual, auditory, etc.) construction to show another agent, with a goal of causing the other agent to experience phenomena similar to what they would experience upon experiencing some particular entity in the shared environment e Intentional communication, in which an agent explicitly communicates to another agent what its goal is in a certain situation ! It is clear that ordinary everyday communication between humans possesses all these aspects. We define the Embodied Communication Prior (ECP) as the probability distribution in which the probability of an entity (e.g. a goal or environment) is proportional to the difficulty of describing that entity, for a typical member of the community in question, using a particular set of communication mechanisms including the above five modes. We will sometimes refer to the prior probability of an entity under this distribution, as its “simplicity” under the distribution. Next, to further specialize the Embodied Communication Prior, we will assume that for