Gain scores are obtained as the difference between two consecutive measurements of knowledge. Although they arewidely acknowledged as a measure of change, they have been harshly criticized since empirical research has shown itsserious conceptual problems. To gain insight on the nature of these problems, I developed a model for the gains ofknowledge in the setting of a pretest-posttest instructional intervention. The model explains seemingly odd phenomenaassociated to gain scores: (a) negative gain-pretest correlations, and (b) lack of correlations between gain scores andlearner’s cognitive abilities. This highlights the potential of the proposed model for investigating the change of knowledgein a pretest-posttest educational setting and emphasizes the importance of modelling change by using information providedby specific application areas. Further work may lead to developing novel statistical methods for analysing educational dataand for estimating the change of knowledge in diverse educational contexts.

Research in analogical transfer suggests a simple type of transfer that occurs due to the activation of key relational concepts. Analysis on mental structured representations indicates that this transfer may act differently depending upon structural and perceptual features of the priming task. Two hundred eight participants were assigned to three experimental groups where they received a structure-priming, tested once and afterwards they received a perceptual-priming and tested again. As predicted, the effect of structure-priming was found across conditions whereas the effect of perceptual- priming (a six-second animation) was detected only in subjects with high levels of cognitive reflectiveness. These individual differences are interpreted as evidence that only highly reflective subjects were able to process visuospatial cues in the animation and to extract their structural features, hence activating relational concepts that influenced their interpretations of subsequent tasks.