Romariz da Silva Barros

Generalized identity matching-to-sample in Cebus apella

Our interest was whether or not conditions could be created under which capuchin monkeys (Cebus apella) might display generalized identity matching-to-sample (i.e., High accuracy scores on initial tests with stimuli that had not previously appeared on matching-to-sample trials). We employed procedures designed to minimize the effects of several variables that past research suggested might interfere with such emergent matching. These included unwanted stimulus control by location, failure to discriminate defining stimulus features (i.e., Stimulus generalization), and stimulus novelty. In Experiment 1, two monkeys displayed accurate simple simultaneous discrimination with three sets of three stimuli each, presented in any of nine locations on a touchscreen-equipped computer monitor. In Experiment 2, the same monkeys were exposed to a 0-delay identity matching training procedure involving one of the stimulus sets from Experiment 1. After the identity-matching baseline was established, identity-matching tests were presented with other three-stimulus sets (two from Experiment 1 and three new sets). for certain sets, the critical initial identity-matching test was preceded by a history of simple discrimination reversals involving

Reversal learning set and functional equivalence in children with and without autism

To evaluate whether children with and without autism could exhibit (a) functional equivalence in the course of yoked repeated-reversal training and (b) reversal learning set, 6 children, in each of two experiments, were exposed to simple discrimination contingencies with three sets of stimuli. The discriminative functions of the set members were yoked and repeatedly reversed. In Experiment 1, all the children (of preschool age) showed gains in the efficiency of reversal learning across reversal problems and behavior that suggested formation of functional equivalence. In Experiment 2, 3 nonverbal children with autism exhibited strong evidence of reversal learning set and 2 showed evidence of functional equivalence. The data suggest a possible relationship between efficiency of reversal learning and functional equivalence test outcomes. Procedural variables may prove important in assessing the potential of young or nonverbal children to classify stimuli on the basis of shared discriminative functions.

Extent and limits of the matching concept in Cebus apella: A matter of experimental control?

The capacity to exhibit generalized sameness-difference judgments is a hallmark of cognition that is regularly exhibited by humans. As yet, that capacity has not been well documented in New World monkeys such as the capuchin (Cebus apella). This article presents data obtained with 6 capuchin monkeys with a variety of procedures that might lead to generalized identity matching-to-sample (MTS) in this species, reporting part of a research program conducted to evaluate methods for assessing the species’ relational learning capacity. Our working hypothesis is that past failures to demonstrate relational learning have been caused by procedural insufficiency rather than a lack of capacity. Thus far, 6 capuchin monkeys have been test,ed for generalized identity MTS. The apparatus was a touchscreen-equipped microcomputer-controlled experimental chamber. Eleven sets of 3 visual stimuli (black shapes on gray backgrounds) were used. The general procedure was comprised of 4 phases: (a) simple discriminations, (b) repeated shifts of simple discriminations, (c) identity MTS training, and (d) generalized identity MTS tests. Every subject was exposed to each of the phases. Positive results on generalized identity MTS tests were obtained in all of the animals, although there have been substantial differences across individuals. The animal tested most recently has performed at levels comparable to typically developing preschool children.

A note on select- and reject-controlling relations in the simple discrimination of capuchin monkeys (Cebus apella)

Controlling relations in the simple discrimination performances of capuchin monkeys (Cebus apella) were studied in two experiments using a blank-comparison procedure. The main goal was to determine whether monkeys would (a) select an S+ stimulus if another stimulus was substituted for the S- (indicating a select-controlling relation) and (b) reject an S- if another stimulus was substituted for S+ (indicating a reject-controlling relation). In experiment 1, two simple simultaneous discriminations were established, one of which was reversed repeatedly until rapid reversal learning was exhibited. During subsequent probe tests, some behavior was consistent with select- and reject-controlling relations, but there was also substantial variability. To control the variability, the procedures of experiment 2 were designed to establish select- and reject-control relations directly by training with the blank-comparison procedure. On subsequent probe trials, new stimuli were substituted for the blank comparison. Both animals exhibited consistent, reliable select- and reject-controlling relations. These experiments are the first to employ the blank-comparison procedure with non-human subjects. They also demonstrate a reliable method for generating select- and reject-controlling relations for experimental study.

Testes de identidade generalizada com objetos em macaco-prego (Cebus apella)

Capuchin monkeys show generalized identity (GI) when tests are preceded by repeated shifts of simple discrimination training (RSSD) with stimuli used in tests. The present study evaluated if that facilitating effect of RSSD training could be due exclusively to the previous contact with the testing stimuli. It was given to a male capuchin monkey four GI tests with objects: Test 1 - an identity conditional discrimination task with new stimuli; Test 2 - with the same stimuli used in Test 1 after RSSD training to induce conditional control; Test 3 - with new stimuli, freely manipulated by the subject previously; and Test 4 - with the same stimuli used in Test 3 after RSSD training. The subjects performance reached the learning criterion in Tests 2 and 4. RSSD training was more effective than free manipulation to produce immediate matching to sample with new stimuli.

Matching-to-sample as a model of symbolic behavior for bio-behavioral investigations.

This paper discusses the use of matching-to-sample as a procedure to investigate symbolic behavior acquisition when studying the evolution of language. It is argued that generalized identity and stimulus classes formed after learning arbitrary interconnected conditional stimulus relationships may be the result of basic pre-symbolic processes. Such aspects may thus provide relevant information for interdisciplinary research on symbolic behavior and language evolution. An individualized approach when building matching-to-sample repertoires - different from that of traditional training - is described. As an example, the results of a generalized identity matching-to-sample procedure held with an experienced capuchin monkey are presented.

Celos: Test de Definición y una Hipótesis sobre la Diferencia de Género bajo la Óptica del Análisis de la Conducta

Resumen es: El articulo describe resultados de una investigacion que intento probar una defi nicion de los celos, asi como una hipotesis para la diferencia del gene...

Simple Successive Discrimination and Functional Class Formation in Preschool Children

The present study evaluated the effectiveness of a simple successive (go/ no-go) discrimination procedure in producing functional class formation as a systematic replication of a previous study with simple simultaneous discrimination. Five preschool children learned 3 simple discriminations and were given repeated reversal training with all 6 stimuli simultaneously. Four of these children learned a fourth discrimination and a new series of reversals with 8 stimuli. Rapid reversals (learning set) occurred with 6 stimuli in 3 children and 8 stimuli in 4 children. Two children presented performance compatible with functional class formation. The results were similar to those reported in the previous study. Similar to the simultaneous procedure, the successive procedure effectively generated functional class formation with some, but not all, of the participants. The occurrence of errors inherent to the reversal procedure may be a source of variability. Future research should investigate other strategies to promote stimulus class formation on the basis of shared discriminative functions.

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.

A NOVEL METHOD FOR TEACHING THE FIRST INSTANCES OF SIMPLE DISCRIMINATION TO NONVERBAL CHILDREN WITH AUTISM IN A LABORATORY ENVIRONMENT

A novel method for initiating discrimination training with nonverbal children combines a delayed S+ procedure that requires children to refrain from responding to either of 2 physically different choice stimuli until a prompt stimulus is added onto 1 of the choices, and a delayed prompting procedure that presents the same 2-choice stimulus display, but stimuli are initially added onto both choices. After a short delay, the added stimulus on the S- is removed, and the choice of the S+ is thus prompted. If the children learn to observe and respond to the defining features of the S+ choice stimulus, then they may respond to the S+ prior to the added-stimulus removal. Implementation was successful with 8 nonverbal children who had not previously exhibited simple simultaneous discrimination, suggesting a useful methodology for initiating discrimination training with populations for whom verbal instruction is ineffective.