Dear blog reader,
This month, we have a contribution from Professor Renato Bortoloti. We are delighted that Renato agreed to tell us a bit about his research story here, a story that involves an interesting journey exploring ways and means of assessing derived relational responding as a model of natural symbolic relations. In doing so, Renato’s work has drawn on a range of different fascinating areas and methodologies, including the equivalence paradigm and electrophysiology, to name but a few. In drawing on these various elements, his research has made, and continues to make, a vibrant and compelling contribution to the behavior-analytic study of symbolic language and thought. And to top it off, he is a genuinely nice guy and is always a pleasure to interact with. So, we invite the reader to sit back and enjoy Renato’s inspiring research story — take it away Renato!
Colin and Dermot
About the author:
Renato Bortoloti is a professor at the Federal University of Minas Gerais (UFMG), Brazil, where he is affiliated with the graduate programs in Psychology: Cognition and Behavior, and Neurosciences. His primary areas of interest are basic psychological processes, experimental psychology, basic language processes, and electrophysiology of symbolic function. He is also a member of the Scientific Directorate of the National Institute of Science and Technology on Behavior, Cognition, and Teaching (INCT-ECCE), a network that brings together researchers from various Brazilian universities and numerous international collaborators.
A Brief Research Story on Measuring the Strength of Symbolic Relations
(clique aqui para a tradução em português deste blog)
To speak a bit about my research story, I think I should return to the year 1996, when I joined the newly created undergraduate Psychology program at the Federal University of São Carlos (UFSCar), Brazil. At the beginning of that academic year, the vague image I had of the process of knowledge production in psychology became more defined, captivating, and enticing, especially when I started studying the foundational works of different lines of investigation during a course taught at the time by Professor Deisy de Souza. As I delved into these fascinating works and the subsequent studies they inspired, I increasingly felt that I could achieve professional fulfillment (and a great deal of personal satisfaction) by contributing to the world of scientific research. I can say that I was fortunate to find at UFSCar the right conditions to test the validity and consistency of this initial impression.
Throughout the undergraduate program, UFSCar Psychology students must engage in various research projects in addition to the activities traditionally offered in behavior analysis teaching laboratories. I had the opportunity to participate in diverse projects that explored, for example, the elevated plus maze model to test the anxiolytic or anxiogenic effects of substances administered to mice, the training of simple and conditional discriminations in bees, and reading and writing in at-risk children, among others. Additionally, I received a scientific initiation scholarship to conduct experiments on learned helplessness in rats, under the guidance of Professor Julio de Rose. Still during my undergraduate studies, as part of a course activity, I had the chance to replicate a study involving exclusion-based learning and the formation of equivalent stimulus classes. This work contributed to my in-depth study of the stimulus equivalence paradigm, which sparked my interest in the remarkable possibilities that a behavioral model of symbolic function could offer.
I joined the master’s program in Theory and Research of Behavior at the Federal University of Pará (PPGTPC/UFPA) in 2001 and completed my PhD in the same program in 2007. During this entire period, my advisor was Professor Olavo Galvão. Although formally affiliated with UFPA, my work was actually conducted at UFSCar, under the supervision of Julio de Rose. The choice of formal affiliation with UFPA was due to several factors: the lack of a graduate program in psychology at UFSCar at that time, the previous collaboration between Professors Julio and Olavo, the opportunity to closely observe (and potentially collaborate with) the fascinating work on the symbolic potential of capuchin monkeys developed by Olavo, and finally, PPGTPC/UFPA’s acceptance of a remotely located student. Thus, I spent the six years of my graduate studies frequently traveling to Belém, but I was mostly in São Carlos, working to validate stimulus equivalence as a model of meaning and investigating the quantitative properties of experimentally simulated symbolic relations, as I will explain below.
Based on an idea from Professor Julio de Rose, my master’s work was developed to test the validity of the equivalence model as an experimental model of semantic relations using a widely accepted measure of meaning: the semantic differential. The semantic differential is a technique used to measure the meaning that participants attribute to “concepts” (words, photographs, drawings, etc.) presented to them. This instrument allows for the quantification and comparison of the meaning of one or several concepts, for one or several individuals, in one or several situations. Broadly speaking, the proposal that guided the main study I conducted during my master’s can be summarized as follows: if it is true that equivalence relations simulate symbolic relations, then equivalent stimuli should share meanings, and the semantic differential should capture this shared meaning. This study provided empirical validation of equivalence as a model of semantic meaning and proposed a new methodology for investigating the transfer of functions, which I explored further in my PhD studies.
In addition to validating stimulus equivalence as a model of meaning, such methodology was effective in determining differences in the level of transfer of meanings in equivalence classes formed using distinct experimental parameters. Variations in transfer of functions indicate variations in the relatedness of equivalent stimuli. The studies conducted show, for example, that the degree of meaning transfer can systematically vary according to the delayed presentation of comparison stimuli in matching-to-sample trials (Bortoloti & de Rose, 2009), the number of intervening nodes in established relations, and the amount of training (Bortoloti et al., 2013). This methodology was sensitive to these and other manipulations (e.g., Bortoloti & de Rose, 2011). Using only traditional matching-to-sample procedures would not be sufficient to capture the quantitative variations found in the mentioned studies. Matching-to-sample procedures establish contingencies of forced choices between discrete alternatives, which can only determine whether the participant has formed equivalent stimulus classes or not. It is not possible to determine if the stimuli within the formed classes are equally related to each other.
Evaluating the strength of symbolic relations has been one of the focal points of the research I have helped develop for a long time. The assessment strategies include psychometric measures, such as the semantic differential; behavioral measures, such as the Implicit Relational Assessment Procedure (IRAP); and electrophysiological measures, as described below. Results from other laboratories had already demonstrated that the establishment of equivalence relations between arbitrary stimuli can modulate the brain waveform known as N400, considered an electrophysiological signature of semantic relations (Barnes-Holmes et al., 2005; Haimson et al., 2008). We replicated these results and argued that the amplitude and latency of the N400 component, often taken as continuous measures of participants’ fluency in symbolic relations, can be sensitive to experimental parameters that influence the establishment of relations between stimuli (Bortoloti et al., 2014). This hypothesis was tested and corroborated by Espírito-Santo et al. (2019).
I began exploring the IRAP in 2009 when we conducted a study to evaluate the formation and strength of experimentally simulated symbolic relations. The results we obtained replicated some that we had already achieved with the semantic differential, which encouraged me to continue using the IRAP in various studies in subsequent years. In this initial study, two groups of participants were trained to establish equivalence classes between faces expressing emotions and nonsense words, and then they were subjected to an IRAP designed to assess the strength of the established relations. This study showed that equivalence relations, when generated through a delayed matching-to-sample procedure, produced a more robust IRAP effect than equivalence relations generated through a simultaneous matching procedure. A manuscript describing this study was submitted to The Psychological Record and received very positive feedback, eventually being published in 2012 (Bortoloti & de Rose, 2012). I remember that one of the reviewers revealed his identity; it was the IRAP’s creator, Dr. Dermot Barnes-Holmes. I met Dermot in person a few years later, and today I have the privilege of collaborating with him on several projects.
The study described above revealed an intriguing and unexpected result at that time: positive and negative emotional faces seemed to differentially influence the strength of experimentally simulated symbolic relations, as suggested by the analysis of the obtained IRAP effects. Specifically, participants exhibited a stronger (i.e., larger) IRAP effect in trials involving happy faces and their equivalent pseudowords, and a weaker IRAP effect in trials involving angry faces and their equivalent pseudowords. The significant difference between these effects suggested that the relations among the members of the equivalence class involving happy faces were stronger than the relations among the members of the equivalence class involving angry faces. Additionally, a reanalysis of data obtained with the semantic differential in studies that also involved the formation of equivalence classes between human faces expressing emotions and arbitrary stimuli corroborated this hypothesis: it revealed a greater magnitude of transfer of function in stimulus classes involving happy faces compared to classes involving negative faces. We realized we were observing something new, not yet described in the behavior analysis literature, although mainstream psychology pointed to a (controversial) happiness superiority effect in some contexts, especially in experimental situations involving the face-in-the-crowd paradigm.
Naturally, we decided to systematically replicate these findings using both the semantic differential (e.g., Bortoloti et al., 2013) and the IRAP (Bortoloti et al., 2019; 2020; Schmidt et al., 2021), and the “happiness superiority effect” in experimentally simulated symbolic relations proved to be robust. A current interpretative effort of these results has benefited from recent interpretative models contained in the updated version of Relational Frame Theory (RFT) proposed by Drs. Dermot Barnes-Holmes, Colin Harte, and collaborators (e.g., Barnes-Holmes & Harte, 2022), where the functional properties of stimuli must be considered in the analysis of the establishment of symbolic relations between them. We have conducted several studies that confirm assumptions presented in these interpretative models (e.g., Pinto et al., 2020; Bortoloti et al., 2023), but a comprehensive description of these works is beyond the scope of this narrative.
To conclude, I would like to say that the research activities I have described above are part of the core basic research of the National Institute of Science and Technology on Behavior, Cognition, and Teaching (INCT-ECCE), a network that brings together researchers from eight different Brazilian universities and several international collaborators. Coordinated by Dr. Deisy de Souza, INCT-ECCE focuses on the science and technology of behavior, addressing symbolic functioning and deficits in symbolic repertoires. This network integrates basic, translational, and applied research into a multidimensional program. The basic research core of INCT-ECCE is dedicated to developing new knowledge and methodologies relevant to understanding symbolic function. Measuring the strength of symbolic relations under different experimental conditions has been one of the focuses of my research and may eventually benefit the translational and applied cores in developing more effective teaching procedures for symbolic repertoires. I had the privilege of witnessing the conception, development, and consolidation of INCT-ECCE while I was still at UFSCar, and I am very grateful to Drs. Deisy de Souza and Julio de Rose, who led this initiative.
References
Barnes‐Holmes, D., & Harte, C. (2022). Relational frame theory 20 years on: The Odysseus voyage and beyond. Journal of the Experimental Analysis of Behavior. https://doi.org/10.1002/jeab.733
Barnes-Holmes, D., Staunton, C., Whelan, R., Barnes-Holmes, Y., Commins, S., Walsh, D., Stewart, I., Smeets, P. M., & Dymond, S. (2005). Derived stimulus relations, semantic priming, and event-related potentials: testing a behavioral theory of semantic networks. Journal of the Experimental Analysis of Behavior, 84, 417-433. doi: 10.1901/jeab.2005.78-04
Bortoloti, R., de Almeida, R. V., de Almeida, J. H., & de Rose, J. C. (2019). Emotional faces in simbolic relations: a hapiness superiority effect involving the equivalence paradigm. Frontiers in Psychology, 10, 1 – 12. https://doi.org/10.3389/fpsyg.2019.00954
Bortoloti, R., de Almeida, R. V. de, Almeida, J. H., & de Rose, J. C. (2020). A commentary on the dynamics of arbitrarily applicable relational responding involving positive valenced stimuli and its implications for the IRAP research. The Psychological Record. https://doi.org/10.1007/s40732-020-00413-2
Bortoloti, R., & de Rose, J. C. (2009). Assessment of the relatedness of equivalent stimuli through a semantic differential. The Psychological Record, 59, 563-590.
Bortoloti, R., & de Rose, J. C. (2011). An “Orwellian” account of stimulus equivalence. Are some stimuli “more equivalent” than others? European Journal of Behavior Analysis, 12, 121-134.
Bortoloti, R., & de Rose, J. C. (2012). Equivalent stimuli are more strongly related after training with delayed matching than after simultaneous matching: a study using the implicit relational assessment procedure (IRAP). The Psychological Record, 62, 41-54. https://doi.org/10.1007/BF03395785
Bortoloti, R., Pimentel, N., & de Rose, J. C. (2014). Electrophysiological investigation of the functional overlap between semantic and equivalence relations. Psychology & Neuroscience, 7, 183 – 191.
Bortoloti, R., Rodrigues, N. C., Cortez, M., Pimentel, N., & de Rose, J. C. (2013). Overtraining increases the relational strength of equivalent stimuli. Psychology and Neuroscience, 6 (3), 357 – 364.
Bortoloti, R., Schmidt, M., Harte, C., & Barnes-Holmes (2023). Feel the Func: Interpreting IRAP Performances Based on Cfunc versus Crel Stimulus Properties. The Psycological Record, 73, 363–373. https://doi.org/10.1007/s40732-023-00557-x
Dias, G. C. B., Silveira, M. V., Bortoloti, R., & Huziwara, E. M. (2021), Electrophysiological analysis of stimulus variables in equivalence relations. Journal of the Experimental Analysis of Behavior, 115, 296-308. https://doi.org/10.1002/jeab.664
Espírito-Santo, R. R. B., Dias, G. C. B., Bortoloti, R. & Huziwara, E. M. (2020). Effect of the number of training trials on the event-related potential correlates of equivalence relations. Learning & Behavior, 48, 221-233. https://doi.org/10.3758/s13420-019-00389-2
Haimson, B., Wilkinson, K.M., Rosenquist, C., Ouimet, C. & McIlvane, W.J. (2009). Electrophysiological correlates of stimulus equivalence processes. Journal of the Experimental Analysis of Behavior, 92, 245-256. doi: 10.1901/jeab.2009.92-245
Pinto, J. A. R., de Almeida, R. V., & Bortoloti, R. (2020). The stimulus’ orienting function may play an important role in IRAP performance: Supportive evidence from an eye-tracking study of brands. The Psychological Record. doi: 10.1007/s40732-020-00378-2
Schmidt, M., de Rose, J. C, & Bortoloti, R. (2021). Relating, orienting and evoking functions in an IRAP study involving emotional pictographs (emojis) used in electronic messages. Journal of Contextual Behavioral Science, 21, 80-87. doi: 10.1016/j.jcbs.2021.06.005