Who Needs Emotions? The Brain Meets the Robot

216 robots
Being in a state P of a system S is a positively affective state if
being in P or moving toward P changes the dispositions of S so
as to cause processes that increase the likelihood of P persisting
or tend to produce or enhance processes that bring P into existence
or maintain the existence of P.
For example, being in pain is negatively affective since it tends to produce
actions that remove or reduce the pain. Enjoying eating an apple is
positively affective since it involves being in a state that tends to prolong
the eating and tends to resist things that would interfere with the eating. In
both cases, the effects of the states can be overridden by other factors including
further states involving mechanisms that tend to suppress or remove
the affective states, such as satiety mechanisms in animals; that is why the
definitions have to be couched in terms of dispositions, not actual effects.
For instance, masochistic mechanisms can produce pain-seeking behavior,
and various kinds of religious indoctrination can cause states of pleasure to
produce guilt feelings that interfere with those states.
There are many subdivisions and special cases that would need to be
discussed in a more complete analysis of information-processing systems with
affective and nonaffective states. In particular, various parts of the above
definitions could be made more precise. We could also add further details,
such as defining the intensity of an affective state, which might involve things
like its ability to override or be overridden by other affective states and perhaps
how many parts of the overall system it affects. Here, we mention only
three important points.
First, we can distinguish direct and mediated belief-like and desire-like
states. This amounts to a distinction between states without and with an
explicit instantiation in some information structure that the system can create,
inspect, modify, store, retrieve, or remove. If the state is merely implicit
(i.e., direct, unmediated), then the information state cannot be created or
destroyed while leaving the rest of the system unchanged.
In other words, explicit mental states are instantiated in, but are not part
of, the underlying architecture (although they can be acquired and represented
within it), whereas implicit mental states are simply states of the
architecture that have certain effects. Note that “explicit” does not mean
“conscious”, as it is possible for a system to have an explicit instantiation of
an information structure without being aware of it (i.e., while the information
structure is used by some process, there is no process that notices or
records its presence).
Second, some belief-like states and desire-like states are derivative substates
in that they result from a process that uses something like premises
(i.e., preexisting explicit/mediated states) and a derivation of a new explic-