Operator preview effects in multiplication: evidence of absence or absence of evidence?

Previous studies have been equivocal on the role of long-term memory in mental arithmetic. For example, Fayol and Thevenot (2012) interpreted a null operator preview effect in multiplication as evidence for a procedural account of addition. In this study, we performed a Bayesian reanalysis of the null effects in Fayol and Thevenot (2012). We used the BIC Bayes factor and a repeated-measures variation of the Pearson Bayes Factor (Faulkenberry, 2021) to compute the evidence for the null hypothesis directly from Fayol and Thevenot's reported summary statistics. We found only anecdotal evidence to support Fayol and Thevenot's claims of no reaction time speedup for multiplication. Both the BIC Bayes factor and the repeated-measures Pearson Bayes factor were less than 2.3. Whereas Fayol and Thevenot (2012) interpreted their results as evidence of absence of an operator preview effect, our results reveal an absence of evidence.