Comments on a pseudo-mathematical model in social psychology

This paper critically examines the mathematical model, the ‘confluence model’, proposed by Zajonc, Markus and Markus (1979) as part of their analysis of birth order effects on intellectual differences. Five observations are made. The first concerns lack of precision in the indices contained in the model. The second deals with the coherence of the mathematical formulation. The third identifies presumably unanticipated and remarkable universal laws of mental development which can be derived from the model. The fourth identifies a further ‘universal law’ which arises from inappropriate use of terms to qualify parameters in the formulae. Finally, it is concluded that the ‘confluence model’ lacks the features required of a credible and useful mathematical model.