Are “input monitoring” and “response selection” involved in solving simple mental arithmetical sums?

Results from past studies show that the central executive, as conceptualised in the working memory model of Baddeley and Hitch (1974), plays an important role in simple mental arithmetic. According to this model the central executive is viewed as a unitary system. Recent research, however, suggests that the “central executive” can be fractionated in more autonomous executive functions, such as inhibition, response selection, planning, and input monitoring. In four experiments we studied the role of two possible executive functions (input monitoring and response selection) in solving simple sums. Subjects solved one‐digit sums (e.g., 5 + 7) in a single‐task condition as well as in dual‐task conditions. The results show that secondary tasks, which require a choice, impair the calculation of simple sums. On the other hand, an increased degree of input monitoring in the secondary tasks does not seem to impair the calculation of the sums. These findings show that response selection is strongly involved in simple arithmetic and may be one of the core executive processes in mental arithmetic.