Subjects' effort in Fitts Tapping Tasks regarding the task difficulty  

Brecic A., Manenica I.
First author's affiliation: Department of Psychology, University of Mostar, Mostar, BIH

Fitts tapping task (FTT) consists of 12 psychomotor tasks, which difficulty varies from one to six bits. Previous studies where FTT was used, showed a linear decrement in performance and also a linear increment in the task difficulty assessment as the task difficulty objectively increased. Since the tasks consist of motor and mental components, this would mean that the motor component decreases and the mental component increases as the task difficulty increases. In the view of this, it could be argued that summative effort (motor plus mental) which subjects put in the task remains the same throughout the tasks. The aim of this study was to check this hypothesis by using different heart rate parameters as indicators of the total effort put in the task by the subject. If this effort were constant, the cardiac indices would not significantly differ throughout the tasks. Fifteen subjects performed all the tasks for five minutes each, while their cardiac R-R intervals were continuously recorded before, during and after the task. Their performance (number of target hits) was also recorded, together with intertap intervals. At the completion of every task subjects were asked to assess their difficulty on Borg's scale. As expected, the results showed a fall in the number of target hits as the task difficulty increased, and an increase in the task difficulty assessment. The analysis of cardiac R-R intervals included classical analyses, as well as spectral analysis procedure. All the parameters showed differences between the preceding resting and the five-minute working periods. There was no difference, however, amongst the tasks of various difficulties. The results suggest, although the load contents of the tasks change as their difficulty changes, the total effort, put in the task by subjects, remains the same regardless of the task difficulty.