Locus of control and cardiac response to reaction time, mental arithmetic, and time-estimation tasks.

In Exp. 1 subjects, classified on the basis of locus of control scores, performed both reaction time and mental arithmetic tasks. In Exp. 2, similarly classified subjects were required to estimate the duration of a signal with feedback following each trial. Between-groups comparisons in Exp. 1 showed no differences on heart rate or performance measures. This does not support an explanation of differential heart rates during cardiac conditioning based upon cognitive styles of "rejecting" or "accepting" stimuli. Similar comparisons in Exp. 2 indicated significant differences for heart rate and proficiency in time estimation. These differences suggest greater task involvement for internally controlled subjects on feedback tasks, with cardiac acceleration a function of that involvement.