Olavo de Faria Galvão

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

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.

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.

Emergence of Conditional Discriminations after Constructed-Response Matching-to-Sample Training

Mackay (1985) reported that subjects were able to match printed words to colors after learning to construct the color names from a pool of letters. Visual feedback from the constructed color names might have been responsible for the emergent matching to sample. In this study we prevented visual feedback during the construction procedure. Also, in matching-to-sample tests Mackaÿs subjects might simply have reached for the first letter of a comparison name, as if to begin construction, and a selection of the whole word would have been recorded. In this study, subjects constructed combinations of three arbitrary forms, with each combination composed of a different sequence of the same three forms. In the subsequent matching-to-sample test, subjects could not select a comparison on the basis of a single element because all comparisons were made up of the same elements. Even with feedback and element sequence controlled, the subjects showed nearly perfect performances in the matching-to-sample tests. These results indicated that the emergent matching-to-sample performances did not require visual feedback from the constructed stimuli and were not artifacts of the sequence of elements in the comparison stimuli.

Expansão de repertório de relações arbitrárias em Sapajus sp. via exclusão

The procedure of exclusion may expand children’s repertoire of arbitrary relations resulting in errorless learning, but although choice by exclusion has been reported in a variety of species, it is not followed by learning of the new relations. The objective of this paper was to verify if capuchins would choose by 1 Endereço para correspondência: Escola Experimental de Primatas, Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Rua Augusto Corrêa, n° 1, Guamá, Belém, PA, Brasil 66075-110. E-mail: rodolfo.s.campos@gmail.com Trabalho apresentado em sessão coordenada “Responder por exclusão: das abelhas aos universitários, o que aprendemos?”, na XLI Reunião Anual da Sociedade Brasileira de Psicologia, 2011, Belém, PA. Os três autores participam do Instituto Nacional de Ciência e Tecnologia Sobre Comportamento, Cognição e EnsinoINCT/ECCE (Processo Fundação de Amparo à Pesquisa do Estado de São Paulo [FAPESP] 08/577058; Processo Conselho Nacional de Desenvolvimento Científi co e Tecnológico [CNPq] 573972/2008-7). Campos, R. S., Brino, A. L. F., Galvão, O. F. 32 exclusion, and if they subsequently would acquire the new arbitrary relations as outcome of exclusion. The capuchin monkey had previously acquired a repertory of 5 A-B and their symmetric B-A arbitrary relations in delayed-matching to-sample (DMTS) with fi ve or more choices. Using a two-choice DMTS, new A-C relations were introduced using non paired B stimuli as Sto verify exclusion. The subject excluded non paired B and chose the new C stimuli. However, performance was disrupted in trials with only C stimuli as comparisons; training with a blank stimulus substituting either comparison in turns was ineffective. Further studies using trials with more than two comparison stimuli will verify arbitrary relations’ learning in capuchins after exclusion.

Spatial Facilitation in a Probing Task in Wedge-Capped Capuchins (Cebus olivaceus)

Activities ordinarily performed by an animal in a given place may influence the way it behaves towards an object newly found there. We examined the use of probing tools in a group of 4 wedge-capped capuchins (Cebus olivaceus), in the home cage into which we simultaneously introduced two identical apparatuses, one at a site ordinarily used to manipulate objects, and the other at a site mainly used for visual monitoring. We expected that spatial facilitation would occur, i.e., the subjects would be more efficient at the site where manipulative behaviors were more frequently performed. Two monkeys used probing tools to extract syrup from the openings of the apparatuses. Tool use efficiency was higher with the apparatus located at the site where they had performed more manipulative and combinative behaviors. These results are consistent with the hypothesis of spatial facilitation and illustrate the fact that spatial context can be an overwhelming variable that should not be neglected in behavioral research dealing with instrumental tasks.

A novel nonsense mutation in the tyrosinase gene is related to the albinism in a capuchin monkey (Sapajus apella)

BackgroundOculocutaneous Albinism (OCA) is an autosomal recessive inherited condition that affects the pigmentation of eyes, hair and skin. The OCA phenotype may be caused by mutations in the tyrosinase gene (TYR), which expresses the tyrosinase enzyme and has an important role in the synthesis of melanin pigment. The aim of this study was to identify the genetic mutation responsible for the albinism in a captive capuchin monkey, and to describe the TYR gene of normal phenotype individuals. In addition, we identified the subject’s species.ResultsA homozygous nonsense mutation was identified in exon 1 of the TYR gene, with the substitution of a cytosine for a thymine nucleotide (C64T) at codon 22, leading to a premature stop codon (R22X) in the albino robust capuchin monkey. The albino and five non-albino robust capuchin monkeys were identified as Sapajus apella, based on phylogenetic analyses, pelage pattern and geographic provenance. One individual was identified as S. macrocephalus.ConclusionWe conclude that the point mutation C64T in the TYR gene is responsible for the OCA1 albino phenotype in the capuchin monkey, classified as Sapajus apella.