Abstract
In order for a cognitive construct to be accepted as explanatory, it must specify target behaviours, posit antecendent variables, and procedures, whereby the antecedent variables can be measured independently of behavioural changes. It is hypothesised that Pascual‐Leone's Theory of Constructive Operators can serve as explanatory construct in cognitive development and science achievement, by postulating the following antecedent variables: Mental Capacity, Field Factor, and the Mobility‐Fixity Dimension. Empirical evidence in support of the three variables is presented. It is concluded that the antecedent variables based on the Theory of Constructive Operators not only serve as explanatory constructs in cognitive development, but also provide epistemological tools that can be manipulated and have important implications for educational practice.