Page 199 - Socially Intelligent Agents Creating Relationships with Computers and Robots

182 Socially Intelligent Agents

cordance with the social context (as assessed within this social layer). In this
sense, social reasoning is formalized as a form of meta-reasoning.
Social Assessment: To support a variety of social interactions, the social rea-
soning layer must provide a model of the social context. The social situation is
described in terms of a number of static and dynamic features from a particular
agent’s perspective. Static features include innate properties of the character
being modelled (social role and a small set of “personality” variables). Dy-
namic features are derived from a set of domain-independent inference proce-
dures that operate on the current mental state of the agent. These include the
set of current communicative obligations, a variety of relations between the
plans in memory (your plans threaten my plans), and a model of the emotional
state of the agent (important for its communicative role).
Planning: One novel aspect of this work is how the social layer alters the
planning process. Grosz and Kraus show how meta-level constructs like com-
mitments can act as constraints that limit the planning process in support of col-
laboration (for example, by preventing a planner from unilaterally altering an
agreed upon joint plan). We extend this to model a variety of “social stances”
one can take towards other individuals beyond purely collaborative relation-
ships. Thus, the social layer can bias planning to be more or less considerate
to the goals of other participants and model power relationships between indi-
viduals.
Communication: Another key aspect of social reasoning is the ability to com-
municate socially appropriate information to other agents in the virtual envi-
ronment. As with many approaches to social reasoning, the social layer pro-
vides a set of speech acts that an agent can use to convey or request informa-
tion. Just as plan generation should differ depending on the social situation, the
use of speech acts must be similarly biased. A commanding officer in a military
operation would communicate differently and under different contexts than her
subordinates.
Social Control Programs: Rather than attempting to formalize some spe-
cific rules of social behavior, we’ve adopted the approach of providing what is
essentially a programming language for encoding the reasoning of the social
layer. This language provides a set of inference procedures and data structures
for representing an agent’s social state, and it provides a set of control prim-
itives that initiate communicative acts and alter the behavior of the task-level
planning system. A simulation developer has a great deal of latitude in how
they write “social control programs” that inform an agent’s social-level reason-
ing. The strong constraint imposed by this language is that social reasoning is
forced to operate at a meta-level. The control primitives treat plans as an in-
divisible unit. An agent can have multiple plans “in mind” and these can be
communicated and treated differently by the planner, but the social-layer can-
not manipulate or refer to the contents of these plans directly. This concept