Yield as an Essential Measure of Equivalence Class Formation, Other Measures, and New Determinants

Environmental cues can indirectly acquire cocaine-eliciting changes in Heart Rate: A pilot study of derived relational responding, the transfer of function among cocaine users

Identifying the processes by which environmental stimuli can come to influence drug use is important for developing more efficacious interventions. This study investigated derived relational responding and the transfer of differential conditioned effects of environmental stimuli paired with "smoked" cocaine in accordance with the relations of symmetry, transitivity, and equivalence using Heart Rate as the measure of conditioning among 12 adults with significant histories of cocaine use. Match-to-sample (MTS) procedures were used to test for emergent relations among two four-member stimulus groupings. One member of a group was then paired with 25-mg of smoked cocaine and one member of the other group was paired with 0-mg of smoked cocaine. 10 participants completed the MTS protocol: 4 participants demonstrated two four-member equivalence classes, 3 participants demonstrated two three-member equivalence classes and 2 participants demonstrated symmetry only. One participant demonstrated no derived relations. Differential respondent elicited changes in HR was demonstrated in the presence of stimuli paired with smoked cocaine among 4 of the 6 participants completing the conditioning phase; all 4 of the participants demonstrated a bi-directional transfer of these functions in accordance with symmetry. Transfer was not reliably demonstrated in accordance with transitive or equivalence relations. The results suggest that drug respondent elicitation in the context of drug use may be a function of both direct conditioning and relational processes. These findings have implications for studying and understanding the processes by which stimuli in the natural ecology can set the occasion for cocaine use and developing cocaine use disorder.

Equivalence Class Formation in Adults with Severe Behavioral Problems

Stimulus equivalence is a behavioral phenomenon that has been related to complex human behavior (e.g., remembering, cognitive functioning, and symbolic behavior). As a rule, people diagnosed with severe mental disorders (e.g., schizophrenia, bipolar disorder) that exhibit delusional and hallucinatory behavior, and disorganized speech have shown cognitive impairment (e.g., processing speed, reasoning/problem solving). Not enough research has analyzed the stimulus equivalence performance in this population. This study aims to investigate the stimulus equivalence performance in adults diagnosed with severe mental disorders. In particular, this study analyzes the many-to-one (MTO) and one-to-many (OTM) training structures effects, and the simultaneous (SIM) and the simple-to-complex (STC) training and testing protocol effects on equivalence class formation in this population. To achieve it, we analyzed the behavior of 18 participants diagnosed with severe mental disorders in three different conditions (Condition 1 OTM/SIM; 2 MTO/SIM; and 3 MTO/STC). Behavior consistent with stimulus equivalence was found in 11 out of 13 participants who had finished the study (5 participants decided to leave before completing the tasks). STC yielded better results than the SIM protocol. No differences were found between MTO and OTM training structures. Implications and suggestions for further research have been discussed.

Merger and expansion of equivalence classes via meaningful stimuli

The present experiments evaluated the effect of meaningful stimuli on the inclusion of a set of extra-experimental meaningful pictures into equivalence classes using within- and between-subjects designs. There were 35 adult participants in total (N_EXP1 = 22; N_EXP2 = 13). In both experiments, participants were first trained on 6 baseline relations with abstract stimuli (A, B, and C) and assessed on the emergence of three 3-member equivalence classes. Next, they were trained on DA relations and assessed on the inclusion of the D stimuli and a set of meaningful pictures in the equivalence classes. In Experiment 1, D1 and D2 were meaningful written words and D3 was a written pseudoword. In Experiment 2, for 2 groups, D1, D2, and D3 were meaningful words; for another group, D1, D2, and D3 were pseudowords. In both experiments, participants formed the ABC classes and included the D stimuli in the classes. When D was a meaningful word, participants also included a set of pictures potentially related to the word in the ABC class established experimentally. The results have implications for the definition of meaningfulness and contribute to discussions on the impact of test arrangements on emergent responding.

Training sequence effects on emergent conditional discriminations: Replication and extension to selection-based training

We examined the replicability and generality of a previously reported training sequence effect on emergent conditional discriminations in the intraverbal naming task. In Experiment 1, a tact-intraverbal (TI) group learned first to vocally label 6 visual patterns and then to intraverbally relate pairs of verbal labels, whereas an intraverbal-tact (IT) group received the same training in the opposite sequence. Emergent conditional discriminations among pattern stimuli were assessed in match-to-sample (MTS) format. Experiment 2 was identical, except vocal tact and intraverbal training were replaced with selection-based training in which the verbal labels were text stimuli. Compared to the IT sequence, the TI sequence resulted in greater mean accuracy at test (Experiment 1), higher yields (Experiment 2), and shorter reaction times (Experiment 2). Experiment 2 data suggested the TI group's performance might be less dependent on intact intraverbal relations relative to the IT group, but related to participants' reports of visualization during intraverbal training. The results suggest the sequence effect is replicable and occurs in experimental preparations commonly used to study derived stimulus relations. They also provide novel support for the hypothesis that participant behavior during training alters sources of stimulus control available at test.

A descriptive analysis of baseline and equivalence-class performances under many-to-one and one-to-many structures

The purpose of the present experiment was to describe responding as a function of One-to-Many (OTM) and Many-to-One (MTO) training structures and identify baseline performances correlated with the accuracy level in tests for equivalence class formation. Participants were 42 adults assigned to either the MTO or the OTM groups, trained on 24 baseline relations, and assessed on the emergence of three 9-member equivalence classes. Participants in the MTO group presented similar frequencies of responses to each of the comparisons throughout baseline training. Also, the number of trials required to meet the baseline mastery criterion was negatively correlated with test accuracy. Participants in the OTM group presented more variable frequencies of responses to each of the comparisons (participants tended to select some of the comparisons less often than others at the beginning of the training). In addition, the number of reinforced responses to the node presented as a sample during training was positively correlated with the number of correct responses during testing for the OTM group. The experiment contributed to an in-depth stimulus control analysis of baseline and test performances, and its results have implications for understanding potential sources of variability between the training structures.

Translational evaluation of training structures in equivalence-based instruction

We used a laboratory preparation to evaluate the claim that equivalence-based instruction (EBI) is an efficient form of instruction due to eliminating the need for emergent relations to be taught. Three groups of college students received training to establish 3 stimulus classes with 4 members in each class. Two groups received either a linear series (EBI-LS) or a 1-to-many training structure (EBI-OTM group). A control group received complete instruction (CI) that targeted all possible relations between the members of each class. The EBI-OTM group required fewer trials to complete instruction compared to CI, whereas EBI-LS did not. The EBI-OTM and the CI groups performed equally well on a posttest that followed initial attainment of the mastery criterion, whereas the EBI-LS group performed more poorly than the other 2. The groups' performance on a function transfer test did not differ. The results support the claim that compared to CI, EBI is an efficient form of instruction when it follows an OTM structure. However, they also suggest this efficiency advantage cannot be attributed to the fewer relations that need to be taught in EBI, as the EBI-OTM and the EBI-LS groups were trained on the same number of relations.