The Implicit Relational Assessment Procedure (IRAP) has been used as a measure of implicit cognition and to analyze the dynamics of arbitrarily applicable relational responding. The current study employs the IRAP for the latter purpose. Specifically, the current research focuses on a pattern of responding observed in a previously published IRAP study that was difficult to explain using existing conceptual analyses. The pattern is referred to as the singletrial-type-dominance-effect because one of the IRAP trial-types produces an effect that is significantly larger than the other three. Based on a post-hoc explanation provided in a previously published article, the first experiment in the current series explored the impact of prior experimental experience on the single-trial-type-dominance-effect. The results indicated that the effect was larger for participants who reported high levels of experimental experience (M = 32.3 previous experiments) versus those who did not (M = 2.5 previous experiments). In the second experiment, participants were required to read out loud the stimuli presented on each trial and the response option they chose. The effect of experimental experience was absent but the single-trial-type-dominance-effect remained. In the third experiment, a different set of stimuli to those used in the first two was employed in the IRAP, and a significant single-trial-type-dominance-effect was no longer observed. The results obtained from the three experiments led inductively to the development of a new model of the variables involved in producing IRAP effects, the Differential Arbitrarily Applicable Relational Responding Effects (DAARRE) model, which is presented in the General Discussion.Key words: RFT, Relational network, IRAP, trial-type, differentialThe Single-Trial-Type-Dominance-Effect 3The study of derived stimulus relations has been used by many behavior analysts as a conceptual basis for analyzing behaviors that appear to be closely related to human language and cognition. Perhaps the clearest and most self-conscious example of this approach is provided by Relational Frame Theory (RFT; Hayes, Barnes-Holmes, & Roche, 2001).Drawing on the seminal work of Sidman (1971; see 1994, for a book length treatment) on equivalence relations, RFT argued that the functional units of human language and cognition involve a wide range of generalized relational operants, known as relational frames, each possessing three core properties. The first property is mutual entailment and involves a bidirectional relation between two stimuli, such that if A is related to B then B is related to A.The second property is combinatorial entailment and involves three or more stimuli, such that if A is related to B and B is related to C, then A is related to C and C is related to A. The third property is the transformation of functions, which recognizes that any mutual or combinatorial entailment will involve specific behavioral functions. Thus, if A is related to B, and B acquires a mildly appetitive function, the func...