Who Needs Emotions? The Brain Meets the Robot

architectural basis of affect 217
itly represented state. Others are nonderivative substates because they are
produced without any process of reasoning or derivation of one representation
from others but merely arise out of activation of internal or external
sensors and their effects on other subsystems. Derivative states, as defined
here, are necessarily also explicit (but not necessarily conscious). The derivative
ones might also be described as “rational” and the nonderivative ones
as “nonrational” insofar as the former, but not the latter, are produced by
possibly very primitive reasoning processes.
A third point concerns a causal connection between two states that does
not include explicit reasoning but something more like reinforcement learning.
For example, associative learning may bring about a certain type of
action, A, as the “content” of a desire-like state, S, because S is repeatedly
followed by a previously desired state, S'. Thus, S, in which A is desired,
arises because A has been found to be a means to S'. For instance, a rat can
be trained to press a lever because that has been associated with acquiring
food. Thus a desire-like state that tends to cause food-seeking might produce
a desire-like state whose content is pressing the lever. This does not
require the rat to have an explicit belief that pressing the lever causes food,
from which it infers the result of pressing the lever. Having such a belief
would support a different set of possible mental processes from the set
supported by the mere learned desirability of pressing the lever. For instance,
the explicit belief could be used in making predictions as well as
selecting actions.
Likewise, a result of associative learning may be that a particular kind of
sensory stimulation produces a belief-like state because the organism has
learned to associate the corresponding situations with those stimuli. For instance,
instead of only the sound or smell of food producing the belief or
expectation that food will appear, the perception of the lever going down
could produce that belief.
In summary, we have distinguished merely associatively triggered belieflike
and desire-like states from those that are derived by a process of reasoning,
making use of explicit representations rather than simply the causal
consequences of implicit desire-like and belief-like states. The distinction
between derivative and associative affective states will later be of assistance
when distinguishing between different kinds of emotion.
Positive and Negative Affect and Learning
We have defined positive and negative affective states in terms of tendencies
or dispositions to achieve/preserve (positive) or avoid/remove (negative)
some state of affairs. It might be thought tempting to define affect in