Complexity in concept formation

Researches in behavior analysis have studied concept formation and symbolic behavior, especially within stimulus equivalence. This research has shown that novel responding of untrained relations can emerge, following conditional discrimination training. Also, research has revealed that the order and arrangement of stimuli in conditional discrimination training, referred to as training structure, affects the formation of equivalence classes. Most research concerning effects of training structures on equivalence formation has mainly focused on the comparison of many to one (MTO), one to many (OTM), and linear series (LS) training structures. A number of articles have been published and several hypotheses have been put forward concerning this phenomenon, which will be elaborated and discussed in Article 1. This article will lay a historical, theoretical, and empirical ground for the research question in Article 2. The experiment in Article 2, one training structure combining elements of OTM and MTO is compared with LS training structure. 12 participants were trained and tested in these two conditions, and their results were compared with regards to equivalence class formation and reaction time. Incorporating an aspect of complexity in class formation, by means of integrating elements of several training structures in conditional discriminations training, might increase our understanding of concept formation and may be a reasonable scientific direction forwar