Merging meaningful classes and abstract equivalence classes by exclusion.

The current experiment assessed whether relating abstract stimuli with familiar pictures by exclusion would produce the formation of a meaningful equivalence class. Ten participants learned conditional discrimination relations with abstract stimuli and established equivalence classes (ABC classes). They then learned DA (D1A1, D2A2, and D3A3) conditional discriminations with written words as D stimuli; two words (D1 and D2) were meaningful stimuli in the participants verbal community ("Dentist" and "Baker"), whereas the third (D3) was a pseudoword ("Tabilu").

Evidence of precurrent responses expanding equivalence classes in a delayed matching-to-sample task.

Delayed matching to sample (DMTS) increases the probability of equivalence class formation. Precurrent responses can mediate the retention interval in DMTS trials and control the selection of comparisons. In human participants, precurrent responses usually consist of naming the experimental stimuli based on their similarities to meaningful stimuli with preexperimental history.

Mercury in the Amazon: The danger of a single story.

Amazon conservation is essential for the global future. Mercury is currently among the worst global pollutants and most (78.5%) of the South-American emissions are from the Amazon.

Time perception and pain: Can a temporal illusion reduce the intensity of pain?

It is commonly known-and previous studies have indicated-that time appears to last longer during unpleasant situations. This study examined whether a reciprocal statement can be made-that is, whether changes in the perception of time can influence our judgment (or rating) of a negative event. We used a temporal illusion method (Pomares et al.

Modeling VI and VDRL feedback functions: Searching normative rules through computational simulation.

We present the mathematical description of feedback functions of variable interval and variable differential reinforcement of low rates as functions of schedule size only. These results were obtained using an R script named Beak, which was built to simulate rates of behavior interacting with simple schedules of reinforcement. Using Beak, we have simulated data that allow an assessment of different reinforcement feedback functions.

Rachlin's extended self: Influences on a Brazilian research group.

We pay tribute to Rachlin's work stating that researching and writing for posterity is an act of self-control and altruism. We show how Rachlin's work influenced a series of seminars at the University of São Paulo (Brazil) based on his book from 1989, Judgment, Decision, and Choice. This influence is illustrated through two empirical exercises conducted during our seminars, where students were actively involved in data collection and analysis.

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 = 22; N = 13). In both experiments, participants were first trained on six baseline relations with abstract stimuli (A, B, and C) and assessed on the emergence of three 3-member equivalence classes.

Neuromotor examination in unilateral cerebral palsy: Bilateral impairments in different levels of motor integration.

Unilateral cerebral palsy (UCP) usually results in damage to the unilateral pyramidal system. However, the clinical presentation of neuromotor deficits also suggests lesions to the extrapyramidal and cerebellar systems bilaterally. In this study, we developed and tested a behavioral neuromotor examination protocol assessing impairments at three levels of motor integration for children with UCP, also considering impairments of the non-paretic upper limb as well as the influences of the laterality of the lesion.

Equivalence relations do exist before they are tested: Confirmatory evidence revealed by EEG measurements.

We examined equivalence-based N400 effects by comparing EEG data from participants with different experiences with equivalence testing. Before a priming task used in EEG measurement, Group 1 was given only matching-to-sample training trials whereas Group 2 was exposed to matching-to-sample training and equivalence probe trials. We asked whether exposure to the reinforcement contingency was sufficient to bring about an N400 outcome that might indicate potentially emergent equivalence relations or if such a response depended on experience with equivalence tests.

Cooperative responding in rats: II. Performance on fixed-ratio schedules of mutual reinforcement.

Coordinated responses of 5 dyads of rats were investigated under fixed-ratio (FR) schedules of mutual water reinforcement. Coordinated responding was defined as 2 consecutive lever-presses, 1 from each of 2 rats, occurring <.5 s apart.

Motor imagery in children with unilateral cerebral palsy: a case-control study.

Aim: To evaluate whether children with cerebral palsy (CP) are able to engage in a motor imagery task. Possible associations between motor imagery and functional performance, working memory, age, and intelligence were also investigated.

Method: This is a case-control study that assessed 57 children (25 females, 32 males) with unilateral CP, aged 6 to 14 years (mean age: 10y 4mo; SD 2y 8mo) and 175 typically developing (control) children, aged 6 to 13 years (87 females, 88 males; mean age: 9y 4mo; SD 1y 11mo).

Auditory sentence comprehension in children with cochlear implants after simple visual discrimination training with specific auditory-visual consequences.

The present study evaluated the effects of simple discrimination training with specific consequences on auditory comprehension in children with cochlear implants (CIs). Demonstration of auditory comprehension was based on derived conditional relations and the formation of equivalence relations. Participants learned two sets of three simple visual discriminations in which the positive stimulus (S) was a written pseudo-sentence (C1, C2, or C3) or a compound abstract picture (D1, D2, or D3), displayed in the correct orientation.

Murray Sidman: A life of giving.

Murray Sidman's contributions to the science of behavior span many areas including avoidance behavior, coercion and its effects, stimulus control, errorless learning, programmed learning, stimulus equivalence, and single-subject methodology. He was also a great mentor to many and helped shape the discipline we now call behavior analysis. In this memoriam, we briefly highlight his scholarly legacy and share some personal anecdotes.

Motor Imagery Development in Children: Changes in Speed and Accuracy With Increasing Age.

Although motor imagery has been pointed as a promising strategy for the rehabilitation of children with neurological disorders, information on their development throughout childhood and adolescence is still scarce. For instance, it is still unclear at what age they reach a development comparable to the motor imagery performance observed in adults. Herein we used a mental rotation task to assess motor imagery in 164 typically developing children and adolescents, which were divided into four age groups (6-7, 8-9, 10-11, and 12-13 years) and 30 adults.

Effect of motor imagery combined with physical practice on upper limb rehabilitation in children with hemiplegic cerebral palsy.

Introduction: Evidence indicates that motor deficits in hemiplegic cerebral palsy (HCP) impair both motor execution and planning. However, current rehabilitation efforts focus mainly on relieving impairments in motor execution. Motor imagery (MI) is a promising method for stimulating neural networks underlying the planning and control of movements.

Generalization of equivalence relations from photos to objects by preschool children.

Generalized equivalence classes are stimulus classes that consist of equivalent stimuli and other physically similar class-member stimuli. The present study evaluated whether preschool children would form equivalence classes among photos of abstract objects (2D) and show equivalence generalization to the corresponding objects (3D), printed photos (2D stimuli), and to black-and-white drawn pictures (2D stimuli). Six typically developing children were taught arbitrary relations to establish three 3-member equivalence classes with 2D stimuli presented on a computer screen.

Stimulus control in a go/no-go procedure with compound stimuli with pigeons.

Our previous study using a go/no-go procedure with compound stimuli taught pigeons to peck at two-component compounds A1B1, A2B2, B1C1, B2C2 and refrain from pecking at A1B2, A2B1, B1C2, B2C1. Subjects showed training-consistent responding in tests presenting compounds rotated 180° (BA and CB relations) but not recombined (AC and CA relations). It is unclear whether the responses to BA and CB stimuli were controlled by the relation between the components (conditional discrimination) or by the compounds functioning as a unitary stimulus (simple discrimination).