Page 135 - Designing Sociable Robots

breazeal-79017 book March 18, 2002 14:5

116 Chapter 8

In the current implementation, the affective tags for each releaser are specified by the
designer. These may be fixed constants, or linearly varying quantities. In all, there are three
contributing factors to the robot’s net affective state:

• Drives Recall that each drive is partitioned into three regimes: homeostatic, over-
whelmed or under-stimulated. For a given drive, each regime potentiates arousal and
valence differently, which contribute to the activation of different emotion processes.
• Behavior The success or delayed progress of the active behavior can directly influence the
affective state. Success contributes to positive emotive responses, whereas delayed progress
contributes to negative emotive responses such as frustration.

• Releasers The external environmental factors that elicit emotive responses.
Emotion Elicitors
All somatically marked inputs are passed to the emotion elicitor stage. Recall from chap-
ter 7 that the elicitors filter each of the incoming [A, V, S] contributions to determine
relevance for its emotive response. Figure 8.3 summarizes how [A, V, S] values map onto
each emotion process. This filtering is done independently for each type of affective tag.
For instance, a valence contribution with a large negative value will not only contribute
to the sad process, but to the fear, distress, anger, and disgust processes as well.
Given all these factors, each elicitor computes its average [A, V, S] from all the individual
arousal, valence, and stance values that pass through its filter.
Given the net [A, V, S] of an elicitor, the activation level is computed next. Intuitively,
the activation level for an elicitor corresponds to how “deeply” the point specified by

A A A

surprise surprise surprise
fear
interest interest interest
joy distress joy anger joy
calm calm calm
V V V
disgust
boredom boredom boredom
sorrow sorrow sorrow

Closed Stance Neutral Stance Open Stance
Figure 8.3
Mapping of arousal, valence, and stance dimensions, [A, V , S], to emotions. This figure shows three 2-D slices
through this 3-D space.