Page 49 - Socially Intelligent Agents Creating Relationships with Computers and Robots

32 Socially Intelligent Agents

A viable behavioral state corresponds to a coherent distributed process, with
a selected dominant rule instance in each module, confirmed dynamically by
confirmation signals from other modules.

3. Social Plans and Joint Action

We generalized the standard artificial intelligence representation of plan to
one suitable for action by more than one collaborating agent. A social plan
is a set of joint steps, with temporal and causal ordering constraints, each step
specifying an action for every agent collaborating in the social plan, including
the subject agent. The way an agent executes a plan is to attempt each joint
step in turn. During a joint step it verifies that every collaborating agent is
performing its corresponding action and then to attempt to execute its own
corresponding individual action. We made most of the levels of the planning
hierarchy work with social plans, the next to lowest works with a “selfplan”
which specifies action only for the subject agent, and the lowest works with
concrete motor actions. However, the action of these two lowest levels still
depended on information received from the perception hierarchy.
Initial model and a social behavior. To make things more explicit, we’ll
now describe a simple joint behavior which is a prototype of many joint be-
haviors, namely the maintenance of affiliative relations in a group of agents by
pairwise joint affiliative actions, usually called grooming.
The social relations module contained a long term memory of knowledge
of affiliative relations among agents. This was knowledge of who is friendly
with who and how friendly. This module kept track of affiliative actions and
generated goals to affiliate with friends that had not been affiliated with lately.
Each agent had stored social plans for grooming and for being groomed. Usu-
ally a subordinate agent with groom and dominant one will be groomed. We
organized each social plan into four phases, as shown in the figure: orient,
approach, prelude and groom, which could be evoked depending on the current
state of the activities of the agents. Each phase corresponded to different rules
being evoked.
Attention was controlled by the planning modules selecting the agents to
participate with and communicating this choice to the higher levels of percep-
tion. These higher levels derived high level perceptual information only for
those agents being attended to.

4. Autonomy, Situatedness and Voluntary Action
Autonomy. The concept of autonomy concerns the control relationship
between the agent and other agents, including the user. As illustrated in our
example, agents are autonomous, in the sense that they do not receive control
imperatives and react to them, but instead each agent receives messages, and