By Matt Harrington, BCBA · Behaviorist Book Club · Research-backed answers for behavior analysts
Relational Frame Theory is a behavioral account of human language and cognition that emerged from the experimental analysis of behavior. It proposes that humans develop generalized operants called relational frames — the ability to respond to stimuli in terms of their arbitrarily applicable relations to each other, rather than only based on their physical properties. RFT extends the behavior analytic account of language beyond Skinner's Verbal Behavior by providing a detailed analysis of the derived, symbolic processes underlying complex language and reasoning. It is theoretically grounded in radical behaviorism and functionalism, making it fully consistent with behavior analytic principles while extending their application to phenomena that were previously underanalyzed within the framework.
Derived stimulus relations are relations between stimuli that emerge through training without being directly reinforced. The paradigmatic example is stimulus equivalence: if A is trained as the same as B, and B is trained as the same as C, the organism responds to A and C as equivalent without additional training — the A-C relation is derived from the training history. RFT extends this concept to the full range of relational frames that human language employs: not only equivalence, but opposition, comparison, hierarchy, causality, and deictic relations. The importance of derived stimulus relations is that they explain how human verbal behavior can generate novel responses — including complex reasoning, problem-solving, and language understanding — that were never directly reinforced.
RFT identifies two key features that distinguish human language from simpler stimulus control: mutual entailment (if A is related to B in a specific way, a relation between B and A is derived) and combinatorial entailment (if A is related to B and B is related to C, relations among all three stimuli are derived). These properties are arbitrarily applicable — they can be applied to any stimuli based on the contextual cues present, regardless of the physical properties of the stimuli. The arbitrary applicability and bidirectionality of relational frames are what enable the generative, productive character of human language: an infinite range of novel verbal behavior can be generated from a finite relational learning history.
RFT accounts for perspective-taking through deictic relational frames — the I/You, Here/There, and Now/Then frames that form the relational basis of self-other discrimination and theory of mind. From an RFT perspective, perspective-taking difficulties in many autistic learners reflect gaps in the development of deictic framing rather than fixed cognitive deficits. These frames are established through multiple exemplar training on tasks that require the learner to respond from different spatial and temporal perspectives: 'I am here and you are there; now what if you were here and I were there?' PEAK and related RFT-based curricula provide systematic training progressions for developing deictic frames, with research suggesting that improvements transfer to social understanding and perspective-taking performance.
The PEAK Relational Training System is a comprehensive assessment and curriculum tool developed by Mark Dixon and colleagues to teach the relational skills described by RFT to learners with autism spectrum disorder and related developmental disabilities. PEAK is organized into four modules — Direct Training, Generalization, Equivalence, and Transformation — corresponding to a progression from basic operant repertoires through increasingly complex relational responding. It is designed for learners who have developed functional communication but who show gaps in the complex language and reasoning skills that relational framing underpins, including analogical reasoning, category membership, comparison, and perspective-taking. PEAK provides a behavior analytic framework for targeting skills that were previously addressed primarily by speech-language pathology and cognitive approaches.
Transformation of stimulus functions is the RFT process by which the psychological functions of one stimulus are transferred to another through their participation in a relational frame. When a stimulus has been trained as related to another stimulus with established functions, those functions transform in accordance with the relational frame. Clinically, this explains how verbal content — words, images, memories — can acquire powerful behavioral functions through relational history rather than direct conditioning. A word that has been placed in an equivalence relation with a trauma-related stimulus will elicit trauma-related responses. Understanding transformation of stimulus functions helps BCBAs explain why certain verbal antecedents produce strong behavioral responses and informs interventions that target the relational history rather than only the direct conditioning context.
ACT is based on the RFT analysis of language and the ways in which human verbal behavior, while enabling complex problem-solving and planning, also produces suffering through its derived properties. Cognitive fusion — in which derived stimulus relations produce literal, inflexible responses to verbal content as if it were direct reality — is an RFT-described process that underlies many forms of psychological distress. ACT's defusion techniques target this process directly, training clients to respond to verbal content with greater psychological flexibility rather than literal literal-mindedness. Acceptance, mindfulness, and values clarification processes in ACT similarly target RFT-described relational patterns. The explicit RFT grounding of ACT distinguishes it from other third-wave therapies and places it within the behavior analytic scientific framework.
Multiple exemplar training (MET) is the instructional approach that RFT identifies as the mechanism through which generalized relational operants develop. By training the same relational response (e.g., 'same as,' 'opposite of,' 'more than') across a wide variety of exemplars — different stimuli, different contexts, different modalities — the learner abstracts the relational response as a generalized operant applicable to novel stimuli. Without sufficient multiple exemplar training, relational responding remains stimulus-specific and does not transfer to novel contexts. MET is therefore the key instructional procedure in PEAK and other RFT-based curricula, and its adequacy directly determines whether the learner develops genuinely generalized relational frames or only stimulus-specific trained responses.
Before implementing RFT-based interventions such as PEAK or ACT, BCBAs should develop fluency with core RFT concepts including derived stimulus relations, relational framing, mutual and combinatorial entailment, and transformation of stimulus functions. For PEAK specifically, competencies include administering and interpreting the PEAK assessment, understanding the curriculum's four-module structure, designing multiple exemplar training sequences for specific relational targets, and collecting and interpreting the data needed to guide curriculum progression. For ACT, competencies include understanding the ACT hexaflex model, the RFT mechanisms underlying each ACT process, and the clinical skills needed to implement ACT protocols. Supervision from practitioners with established RFT competence is advisable before independent implementation.
RFT provides behavioral accounts of mental events and processes that cognitive psychology typically explains using internal constructs such as mental representations, schemas, and cognitive processing. By analyzing complex language and cognition in terms of relational operants, verbal stimulus functions, and the training history that produces derived relations, RFT explains the phenomena cognitive psychology describes — analogical reasoning, rule-following, self-referential thinking, and language comprehension — without positing internal cognitive structures that are not subject to behavioral analysis. This extension allows behavior analysis to address complex human behavior that falls outside the scope of basic conditioning while remaining within the scientific framework of operant conditioning and functional contextualism.
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All behavior-analytic intervention is individualized. The information on this page is for educational purposes and does not constitute clinical advice. Treatment decisions should be informed by the best available published research, individualized assessment, and obtained with the informed consent of the client or their legal guardian. Behavior analysts are responsible for practicing within the boundaries of their competence and adhering to the BACB Ethics Code for Behavior Analysts.