The Effects of Mental Arithmetic Strain on Behavioral and Physiological Responses

Everyday activities require different levels of mental load depending on both external and internal task demands, and the resulting strain is likely to drastically influence the forthcoming performance. In this study, we aimed to determine how objective and subjective task constraints may respectively impact strain and performance. Thirty participants, recruited for their affinity or avoidance for mental arithmetic, were confronted with calculations of varying difficulty. Data showed that Reaction Times (RTs), as well as electrodermal (EDR) and heart rate (HR) response durations increased along with task difficulty and performance decrement. Good performance elicited weaker sympathetic involvement, attesting that positive emotions are likely to elicit less strain than negative emotions. The “approach” group exhibited longer electrodermal responses than the “avoidance” group, especially when performing difficult computations. The “approach” group also showed increased EDR duration along with increased RT, while the “avoidance” group exhibited decreased EDR duration along with increased RT. Therefore, individuals with mental arithmetic affinity might be more involved than those with avoidance. Finally, HR deceleration prior to mental arithmetic did not vary as a function of the independent variables, thus meaning that attention increased to the same extent regardless of the experimental condition. Thus, the resulting strain depends on task difficulty, response accuracy, and group membership, the most sensitive physiological indices being EDR duration and HR response duration.