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to unpleasant), arousal (aroused to calm), and control
(dominance to submission). There are both computer and
paper and pencil versions of SAM. In this study, a paper
and pencil version of SAM in which each dimension was
presented as a series of five cartoon characters was be
used. For the valence dimension, SAM's facial expression
gradually changes from a smile to a frown. Arousal is
denoted by increased activity in the abdomen to no activity
and wide eyes to closed eyes. Control is represented from a
very large character who gradually shrinks in size to a very
small character.
During both the anticipatory shock and the anticipatory
reward tasks, subjects were asked to rate how they felt
using the SAM. This was done after each block of 10 trials,
so that two ratings were obtained after each of the
following conditions: shock anticipation, anticipation of
no shock, reward anticipation, anticipation of no reward.
Data Reduction
Heart rate
First raw data was examined. Based on the subjects
data as a whole, missing beats and double beats were
estimated and corrected. Next, a computer program was used
to more thoroughly determine missed beats and double beats.
Double beats were removed from the data set. The computer
used the surrounding beats to estimate the missing beats.
Average half second beats/minute were obtained for each