Anticipation of Affective Stimuli

 Anticipation of affective stimuli has also been used to

 elicit emotion. Lang, Ohman, and Simons (1978) described

 the triphasic response of cardiac activity during a 4-8

 second anticipation period. They reported that the onset of

 the preparatory period is characterized by a brief

 deceleration (D1). The initial deceleration is followed by

 an acceleratory peak (Al). Lastly, a deceleration occurs

 which lasts until the end of the preparatory interval (D2).

 D1 is observed when subjects are presented with single pure

 tones which are not followed by other stimuli and is thought

 to be an index of orientation. The acceleratory phase is

 seen in response to an abrupt stimulus or single stimulus

 with an uncomfortable intensity level. Al has been

 interpreted as an index of a defensive reflex. It has also

 been evoked in the absence of noxious stimuli and during

 problem solving or mentation.

 According to Lang et. al (1978), most investigators

interpret the second deceleration, D2, as an index of

anticipation of an overt response. D2, however, has been

conditioned in classical conditioning paradigm even though

no motor response is required. Consequently, D2 has also

been viewed as an index of an attentive set. Similar HR

patterns have been found by Simons, Ohman, and Lang (1979)

in response to anticipation of slides (Simons, Ohman, &

Lang, 1979; Klorman & Ryan, 1980).