Effects of mixing and cueing simple addition and multiplication

Miller and Paredes (1990) found that both children's and adults' performance of simple addition and multiplication tested in mixed-operation blocks was slower and more susceptible to operation errors (e.g., 6 + 2=12 or 6×2=8) compared to pure-operation blocks; but mixed-operation costs were greater for addition than for multiplication. We pursued the source of these effects in adults (n=96) by examining effects of operation switching and cueing. We replicated the asymmetrical costs of mixing addition and multiplication and demonstrated that these owed, in part, to asymmetrical task switching costs. Operation foreknowledge (a visual cue appearing 2 s before the problem) moderated both mixing and switch costs. This suggests that an asymmetry between addition and multiplication in the utility of preparation contributed to asymmetric mixing costs. Miller and Paredes proposed that the asymmetric costs of mixing operations observed in adults echoed an asymmetry developed in childhood when multiplication is initially learned. This might be correct, but our results raise the possibility that the asymmetry reflects operation-specific costs and interference effects that arise during the experiment.