124

 reward compared to no-reward trials (mean=.219, sd=.564), [Z

 = -3.95, P < .001].

 There were no group differences in the ratings of

 valence, arousal, and dominance. See Table C-68 in Appendix

 C for details.

 Subjects reported experiencing less pleasantness, more

 arousal, and less dominance during the shock compared to the

 reward task. There were no group differences in these

 ratings.

 Medication effects

 All medications that the subjects were taking at the

time of the experiment were recorded. Groups differed in

the amount of medications that affect the autonomic nervous

system, including alpha and beta adrenergic blocking agents,

calcium channel blockers, ACE inhibitors, and digoxin.

Eleven of the RHD subjects were taking these medications, 9

of the LHD, 3 of the RH NCS and 4 of the LH NCS. Thus, the

significant skin conductance analyses were reanalyzed using

the presence of medications that affect the autonomic

nervous system as a covariate.

 Shock :r.diticn. Within the shock task, repeated

measures analyses of covariance were conducted using

percentage of responses with group as the between subject

factor and condition (shock and no-shock) as the within

subject factors. Presence or absence of medication was used

as the covariate. When percentage of responses was examined