Linear mixed effects analysis for RTs for addition and multiplication and for tie and nontie problems, using eight different regressors: the product of the operands (prod), the sum of the operands (sum), its sum squared (sum^2), these three regressors in log scale (log(prod), log(sum), and log(sum^2)), the square root of its products (sqrt(prod)) and its sums (sqrt(sum)), and the min operand.

Bold letters indicate best fit, i.e. minimum AIC value. Observe that in the tie cases, the min, sqrt(prod) and sum regressors represent the same condition.