Detection threshold for electric shock in psychopaths.

A 4-interval forced-choice procedure was used to determine the detection threshold for electric shock in psychopathic and nonpsychopathic criminals. The use of a constant-current stimulator, a concentric electrode, and monitoring of the skin-electrode impedance permitted precise control over the characteristics of shock administered. The results indicated that the psychopathic Ss had a significantly higher detection threshold than did the nonpsychopathic Ss. Several interpretations of these findings were offered, along with some comments on their implication for fear-conditioning and avoidancelearning studies with psychopaths. While the psychopath performs well in a variety of learning situations (e.g., Bernard Eisenman, 1967; Fairweather, 1953; Sherman, 1957), he apparently does not learn to avoid punishment as readily as do normals (Lykken, 1957; Schachter Latane, 1964; Schoenherr, 1964). Since avoidance learning may be mediated by fear reduction (e.g., Solomon Wynne, 1954), it is possible that the psychopaths relative failure to avoid punishment is related to the difficulty with which he acquires the appropriate fear responses (Hare, 1965a, 1965b; Lykken, 1957). Consistent with this view is the recent finding that psychopaths show little evidence of emotional arousal (conditioned anticipatory responses) prior to an impending noxious stimulus (Hare, 1965c; Lippert, 1965). A recent study by Schoenherr (1964) raised the possibility that the relatively slow fear conditioning and avoidance learning of the psychopath may be related to a higherthan-normal threshold for the detection of noxious stimulation. Schoenherrs data indicated that a group of primary psychopaths had a higher absolute threshold for electric shock delivered to the forearm than did groups of secondary psychopaths and normal controls. The implication, apparently, is that the psychopath may experience any given level of shock intensity as being subjectively less intense than do normal subjects (5s), and