ABSTRACT
This research aimed to study the defence responses of blood-injection-injury (BII) fearful subjects elicited by the preattentive processing of their feared objects and by an abrupt acoustic stimulus. We selected 21 BII fearful subjects and 25 non-fearful controls from an initial sample of 128 women, according to their scores on the Fear Survey Scale (damage subscale) and the Mutilation Questionnaire. Subjects were exposed to a burst of white noise to promote a defence response, and to 48 pictures, depicting mutilations, as well as other affective contents, displayed through a backward masking procedure. Heart rate (HR), skin conductance response (SCR) and corrugator supercilii activity were continuously recorded throughout the task. Both groups showed similar SCRs, EMG activity and cardiac defence responses to the acoustic stimulus, though fearful subjects showed greater initial HR deceleration than controls. While BII fearful subjects displayed the usual defence response when exposed to a non-feared threatening stimulus, the preattentive processing of the pictures did not reveal autonomic differences between fearful subjects and controls. Mutilation pictures, however, evoked the greatest EMG activity, but only in the fearful group. These data further extend previous research on conscious perception of blood-related stimuli in BII fearful subjects, by showing a failure to recruit autonomic defence responses when blood-related pictures appear outside of conscious awareness.
