Predictability of repeated challenge: effects on cardiovascular activity in the type A (coronary prone) behavior pattern.
Fifty-two healthy young adults classified either as Type A (coronary prone) or Type B were randomly assigned to a vigilance task during which observing responses produced targets according to either a predictable (i.e., fixed-interval 90-sec) or a nonpredictable (i.e., random-interval 90-sec) reinforcement schedule. During the task, blood volume pulse, interbeat interval, masseter (EMG) activity, and blood pressure were monitored. Transient peripheral vasomotor constriction and heart rate increases were initiated within an 8- to 12-sec period following target detection with the predictable schedule, with subjects evincing greater responsivity than their nonpredictable schedule counterparts. Type A subjects assigned to the random-schedule evinced significantly shorter heart rate and blood volume pulse response durations than did Type B subjects. Longer postevent EMG elevations were evidenced by subjects assigned to the predictable schedule. No significant blood pressure differences were found among the groups. The impact of challenge-contingent behavior on cardiovascular responsivity and the relevance of attentional processes to this relationship and to cardiovascular risk are discussed.
Zeichner
A
A
Department of Psychology, University of Georgia, Athens 30602.
Allen
J D
JD
Spiga
R
R
Rudd
J
J
Brown
A
A
D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology*; D003327:Coronary Disease / Q000503:physiopathology* / Q000523:psychology; D004198:Disease Susceptibility; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D010507:Periodicity; D013315:Stress, Psychological / Q000503:physiopathology*; D014434:Type A Personality