Effects of the waiting interval and task complexity on pulse rate

Abstract

The background of this study was Lacey’s hypothesis which suggests that in the tasks which require waiting for and reacting to stimuli, deceleration of the pulse rate takes place. Contrary to this, in die situation which requires mental work, die pulse is expected to rise. Lacey argued that in complex tasks which include both of these aspects, the overall effects would be no change in die pulse rate, i.e. waiting would decrease it and mental tasks would raise the pulse rate. The aim of this study was to test this hypothesis by using tasks which included waiting for and mental processing. The investigation included 10 subjects, 18-22 years of age, whose task consisted of 10 or 20 seconds of waiting for die mental task to be presented on the computer screen after die starting signal. Apart from the waiting interval the tasks differed in complexity. During the whole section, which included a resting interval before die tasks, die subject's cardiac R-R intervals were continuously registered via a poligraph on a computer. The analysis of the results showed a fall in the pulse rate during the period of waiting, as could be expected, while die task complexity did not have any significant effects on pulse rate. Therefore, the results of the study did not support Lacey's hypothesis of averaging effects of die waiting interval and die mental processing on pulse rate.