Emergent simple discrimination established by indirect relation to differential consequences

Three experiments examined a discrimination training sequence that led to emergent simple discrimination in human subjects. The experiments differed primarily in their subject populations. Normally capable adults served in the first experiment, preschool children in the second, and mentally retarded adults in the third. In all experiments, subjects learned a simple simultaneous discrimination: When visual stimuli A1 and A2 were displayed together, reinforcers followed selections of A1, the S+, but not A2, the S-. The subjects also learned a conditional discrimination taught with an arbitrary visual-visual matching-to-sample procedure. Comparisons were two additional visual stimuli, B1 and B2, and samples were A1 and A2. Reinforcers followed selections of B1 in the presence of A1 and of B2 in the presence of A2. After the simple-discrimination and conditional-discrimination baselines had been acquired, B1 and B2 were displayed alone (without a sample) on probe trials. Subjects had never been taught explicitly how to respond to such displays. Nonetheless, they almost always selected B1, which was involved in a conditional relation with A1, the stimulus that served as S+ on the simple-discrimination trials. This outcome suggested the formation of stimulus classes during conditional-discrimination training. Through class formation, B1 and B2 had apparently acquired stimulus functions similar to those shown by A1 and A2 on simple-discrimination trials, thereby leading to emergent selections of B1 on the probes.     

Randomized controlled trial of a prenatal focused coparenting consultation for unmarried black fathers and mothers: One-year infant and family outcomes

In the infant mental health field, scant conceptual attention has been given to coparenting and family adaptations of non-white family systems, with no evidence-based, community-informed coparenting interventions responsive to unmarried Black mothers’ and fathers’ life circumstances. This study examined 1-year post-partum child and family outcomes of a novel, modest dosage (six sessions) prenatal focused coparenting consultation (FCC) using randomized controlled trial methodology. One-hundred-thirty-eight expectant families (one or both parents identified as Black/African American) were randomized to an intervention (N = 70) or treatment-as-usual (TAU; control) condition (N = 68). TAU families received navigational support in accessing existing community services for pregnant families. Intervention families received TAU plus 6 dyadic FCC sessions led by a Black male-female Community Mentor team. When infants were three and 12 months old, parents reported on coparenting, father engagement, interparental aggression, depressive symptoms, and infant social and emotional adjustment. Intent-to-treat analyses focusing on 12-month post-partum data indicated significant intervention effects on coparenting, interparental psychological aggression, and infants’ emotional adjustment. Improvement was also seen in depression and father engagement, with gains for both groups. Results suggest FCC delivered by same-race Community Mentors to unmarried Black coparents transitioning to parenthood supports infant and family adaptation during the first year of life.     

Assessing control by elements of complex stimuli in delayed matching to sample.

A series of six experiments examined delayed identity matching-to-sample performances of subjects with mental retardation. The stimuli were either one or two simultaneously displayed forms. When the reinforcement contingencies required that only one form exert discriminative control, all subjects achieved high accuracy scores. However, accuracy scores were substantially lower when the contingencies required discriminative control by two forms, suggesting restricted stimulus control. The decline in matching accuracy appeared to reflect selective losses of conditional control by sample stimuli and shifts in control to features of the comparison stimulus displays. The experiments suggest improved techniques for assessing control by complex stimuli and for evaluating the effects of procedures that seek to broaden restricted stimulus control. The results challenge interpretations based on stimulus-generalization decrement or shared attention.     

Sample stimulus control shaping and restricted stimulus control in capuchin monkeys: a methodological note

This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys (Cebus apella). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The objective was to transform identity matching into arbitrary matching (i.e., matching not based on common physical features of the sample and comparison stimuli). Experiment 1 used a two-comparison procedure. The shaping procedure was ultimately effective, but occasional high error rates at certain program steps inspired a follow-up study. Experiment 2 used the same basic approach, but with a three-comparison matching task. During shaping, the monkey performed accurately until the final steps of the program. Subsequent experimentation tested the hypothesis that the decrease in accuracy was due to restricted stimulus control by sample stimulus features that had not yet been changed in the shaping program. Results were consistent with this hypothesis, thus suggesting a new approach that may transform the sample stimulus control shaping procedure from a sometimes useful laboratory tool to a more general approach to teaching the first instance of arbitrary matching performances to participants who show protracted difficulties in learning such performances.     

High-probability stimulus control topographies with delayed S+ onset in a simultaneous discrimination procedure

Experimenters and teachers use discrimination learning procedures to encourage reliable attending to stimulus differences defined as relevant for their purposes. Put another way, the goal of discrimination training is to establish high-probability stimulus control topographies that are coherent with experimenter or teacher specifications. The present research was conducted to investigate a novel procedure for encouraging stimulus control topography coherence. Participants were 13 adolescents with severe intellectual handicaps. During an initial Condition A, all were exposed to a simultaneous discrimination procedure. Participants could select a form alternating with a black field (S+) or an identical form that did not alternate (S-). Accuracy scores were typically low, and there was little evidence of coherent stimulus control topographies. Subsequently, the procedure was changed. During Condition B, every trial initially presented two identical nonalternating S- forms (Trial State 1). If the participant made no selection for 5 s, one of the forms began to alternate with the black field, and he or she could make the S+/S- discrimination (Trial State 2). Selections during Trial State I prolonged the delay to Trial State 2 until there had been no response for 5 s. During Condition B, S+/S- discrimination accuracy scores improved rapidly and markedly for most participants. Reinstating Condition A often resulted in diminished accuracy scores. This study thus (a) demonstrated a novel procedure for encouraging stimulus control topography coherence and (b) provided support for the interpretation that intermediate accuracy scores may be due to different topographies of stimulus control that co-occur in the same discriminative baseline.     

A sorting‐to‐matching method to teach compound matching to sample

Individuals with developmental disabilities may fail to attend to multiple features in compound stimuli (e.g., arrays of pictures, letters within words) with detrimental effects on learning. Participants were 5 children with autism spectrum disorder who had low to intermediate accuracy scores (35% to 84%) on a computer‐presented compound matching task. Sample stimuli were pairs of icons (e.g., chair–tree), the correct comparison was identical to the sample, and each incorrect comparison had one icon in common with the sample (e.g., chair–sun, airplane–tree). A 5‐step tabletop sorting‐to‐matching training procedure was used to teach compound matching. The first step was sorting 3 single pictures; subsequent steps gradually changed the task to compound matching. If progress stalled, tasks were modified temporarily to prompt observing behavior. After tabletop training, participants were retested on the compound matching task; accuracy improved to at least 95% for all children. This procedure illustrates one way to improve attending to multiple features of compound stimuli.     

Can (elaborated) imagined contact interventions reduce prejudice among those higher in intergroup disgust sensitivity (ITG‐DS)?

Intergroup disgust sensitivity (ITG‐DS) reflects an affect‐laden revulsion toward out‐groups. Previous attempts to weaken its prediction of prejudice have failed. Given that clinical approaches to disgust sensitivity successfully utilize mental imagery, we consider contact simulation interventions. Participants were randomly assigned to control, standard imagined contact, or an elaborated contact condition (elaborated imagined contact [EIC]; detailed imagination involving physical contact with a homeless person, with relaxation instructions). Both contact conditions (vs. control) significantly weakened the link between ITG‐DS and prejudice, yet only EIC weakened the relation between ITG‐DS and out‐group trust. Mediated moderation analysis confirmed that EIC significantly attenuated the link between ITG‐DS and prejudice through increasing trust. Clinically relevant treatments are thus valuable in severing the association between (a) ITG‐DS and (b) lower out‐group trust and greater out‐group prejudice.