Deisy das Graças de Souza

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.

EMERGENT WORD-OBJECT MAPPING BY CHILDREN: FURTHER STUDIES USING THE BLANK COMPARISON TECHNIQUE

Two experiments examined the emergent mapping phenomenon in Portuguese-speaking children aged 3–13, This phenomenon is relevant to developmental psychologists’ interest in ‘last mapping” of new word-referent relations and also to behavior analysts’ interest in behavior that emerges without explicit conditioning. We studied 52 children, using the “blank comparison” matching-to-sample technique described by Wilkinson and McIlvane (1997), The technique allows direct measurement of the stimulus control bases of emergent mapping, for example, to determine whether new words and their referents are related directly or via rejection (i.e., exclusion) of previously defined referents. Children demonstrated both types of controlling relations. These studies systematically replicate prior emergent mapping research in a large cohort of non-English-speaking children. Also found were apparent developmental differences between older and younger children. Although all children tended to relate novel stimuli, the tendency appeared to decline as children aged. This study confirms the utility of the blank comparison technique in emergent mapping research and also provides the first data set from school-aged children.

REORGANIZATION OF EQUIVALENCE CLASSES AFTER REVERSAL OF BASELINE RELATIONS

Pilgrim and Galizio (1995) reversed baseline conditional discriminations after the emergence of equivalence classes. College students’ performance was consistent with the reversed baselines in subsequent symmetry tests, but was consistent with prereversal baselines in transitivity tests. The present study replicated systematically Pilgrim and Galizio’s experiment. Following the emergence of two four-members equivalence classes, 9 college students were exposed to reversal of a baseline conditional discrimination, training of a new conditional discrimination, reversal of another baseline conditional discrimination, and return to the original baseline. Both symmetry and transitivity performances were consistent with the reversed baselines for most participants. These results may be due to increased strength of the reversed baselines, trained with continuous reinforcement and reviewed before probes, whereas Pilgrim and Galizio trained reversals with intermittent reinforcement in the context of probing. The use of different stimuli and stimulus display may have also affected the results.

Responder por exclusão em crianças de 2 a 3 anos em uma situação de brincadeira

Laboratory studies have repeatedly replicated the phenomenon of exclusion responding, which has been assumed as one of the mechanisms by which children learn to relate novel words to objects or events. The present study, conducted with six children, aimed to investigate exclusion responding in a play setting, with stimuli that could be manipulated, and to verify whether the play setting would favor learning of the relationships between names and objects after a single exclusion trial. In several trials the experimenter spoke the name of a familiar toy and the childs task was to pick this toy up and throw it into a box, placed in front of the child. Three exclusion probes were interspersed among these trials (the spoken name was novel and there was a novel toy available); three other probes verified whether the relationships between the novel name and the toy had been learned. All children responded by exclusion but only one of them demonstrated learning the relationships in a single trial.

Investigação do controle por regras e do controle por histórias de reforço sobre o comportamento humano

This study investigated the role of experimental history and of relative density of reinforcement on rule following behavior. Sixteen undergraduate students participated. Under a matching-to-sample procedure, with 3 comparison stimuli, the participants were asked to point the comparisons in sequence, according to their dimension, Color, Thickness or Form, in common to the sample. At the beginning of Phases 1, 2, 3 and 4, participants were exposed, respectively, to minimal instructions, a discrepant rule (specifying a non reinforced sequence), a corresponding rule (specifying a TFC sequence) and a repeated discrepant rule. Only the CTF sequence was reinforced in all phases. In Phase 3, two sequences, TFC and CTF, were concurrently reinforced (Concurrent FR 2 FR6 and FR2 FR6). Control by rules and by reinforcement history were both observed, under specific conditions. These findings have implications for drawing a distinction between behaviors controlled by rules and those shaped by contingencies.

A comparative study of relational learning capacity in honeybees (Apis mellifera) and stingless bees (Melipona rufiventris).

Background Learning of arbitrary relations is the capacity to acquire knowledge about associations between events or stimuli that do not share any similarities, and use this knowledge to make behavioural choices. This capacity is well documented in humans and vertebrates, and there is some evidence it exists in the honeybee (Apis mellifera). However, little is known about whether the ability for relational learning extends to other invertebrates, although many insects have been shown to possess excellent learning capacities in spite of their small brains. Methodology/Principal Findings Using a symbolic matching-to-sample procedure, we show that the honeybee Apis mellifera rapidly learns arbitrary relations between colours and patterns, reaching 68.2% correct choice for pattern-colour relations and 73.3% for colour-pattern relations. However, Apis mellifera does not transfer this knowledge to the symmetrical relations when the stimulus order is reversed. A second bee species, the stingless bee Melipona rufiventris from Brazil, seems unable to learn the same arbitrary relations between colours and patterns, although it exhibits excellent discrimination learning. Conclusions/Significance Our results confirm that the capacity for learning arbitrary relations is not limited to vertebrates, but even insects with small brains can perform this learning task. Interestingly, it seems to be a species-specific ability. The disparity in relational learning performance between the two bee species we tested may be linked to their specific foraging and recruitment strategies, which evolved in adaptation to different environments.

Diferenças individuais na aquisição de leitura com um sistema lingüístico em miniatura

This study reports the use of a miniature linguistic system in order to investigate reading acquisition. Twenty college students, 10 from Natural Sciences and Engineering (NSE) and 10 from Health and Social Sciences (HSS) courses, learned to relate pictures and printed pseudo-words to dictated pseudo-words in conditional discrimination tasks presented by a computer. Teaching sessions were interspersed with tests of reading new words formed by recombination of elements of taught words (generative recombination). Nine students from NSE and four from HSS developed generalized reading after learning 12 relations with pseudo-words. Reading scores of new words increased as number of taught words increased. Both findings could be interpreted as effects of learning experiences with symbolic relations. Differences between the NSE and the HSS students could also reflect motivational factors.

Recombinative reading derived from pseudoword instruction in a miniature linguistic system

A miniature linguistic system was used to study acquisition of recombinative symbolic behavior. Three studies evaluated the teaching conditions of conditional discriminations with printed and spoken pseudowords that could potentially generate recombinative reading. Fifty-four college students across all studies learned to match 12 printed pseudowords to 12 spoken pseudowords. Some also matched pictures to the same spoken words. Each two-syllable pseudoword was formed by symbols from an arbitrarily created alphabet composed of four vowels and four consonants. Letters had univocal correspondence with phonemes. Recombinative receptive reading, comprehensive reading, and textual responding to pseudowords were periodically assessed. Experiment 1 (n  =  20) showed that recombinative reading increased as the number of trained words composed of the same symbols increased. Experiment 2 (n  =  14) showed that overtraining the same two words did not produce recombinative reading for most participants. Experiment 3 (n  =  20), in which training with pictures was omitted, showed that elemental control by within-syllable units can develop even when the trained pseudowords are meaningless (not related to pictures). The present results support the utility of the miniature linguistic system methodology for identifying and controlling environmental determinants of rudimentary reading skills.

Formação de classes ordinais após a aprendizagem de seqüências independentes

Abstract The formation of ordinal classes derived from learning independent sequences. The acquisition of ordinalrelations between arbitrary stimuli is an important behavioral skill required in learning academic behaviorsand literacy. The purpose of this study was to investigate the effects of teaching overlapping adjacent two-term sequences on the emergence of ordinal relations with more than two stimuli. Overlapping occurs whenthe last stimulus in one sequence of two stimuli is the first stimulus in another sequence (e.g., S1 → S2 andS2 → S3, where S2 is the overlapped stimulus). Two-term sequences were taught in Phases 1 and 2 of anexperiment conducted with five first grade students. Sequences A were taught with stimuli from sets A (A1→ A2, A2 → A3, A3 → A4, A4 → A5) and Sequences B with stimuli from set B (B1 → B2, B2 → B3, B3→ B4, B4 → B5). Once this baseline was established, tests verified the emergence of ordinal relations withthree, four and five stimuli from sets A and B, separately. Phase 3 evaluated if stimuli from Sequences A andB were substitutable one for one another, on the basis of the same ordinal functions (the first, the second,etc.). The students learned all trained ordinal relations and showed the emergence of new (and longer) ordinalrelations with stimuli of sets A and B stimuli, separately. Three students also showed substitutabilitybetween A and B stimuli in Phase 3. These findings suggest the formation of five stimuli classes, each oneconsisted of stimuli that occupied the same ordinal function in different sequences. These results suggest theemergence of five stimulus classes (A1B1, A2B2, etc), each one with stimuli that occupied the same ordinalfunction in different sequences. The results have implications for the analysis of complex symbolic behavior.Some methodological aspects seemed to have contributed for the occurrence of relational learning and theemergence of novel behavior.

Leitura recombinativa de pseudopalavras impressas em pseudoalfabeto: similaridade entre palavras e extensão da unidade ensinada

Controle discriminativo por elementos textuais e requisito para a leitura de palavras novas (leitura recombinativa). Este estudo empregou pseudopalavras ditadas e impressas em pseudo-alfabeto para avaliar os efeitos da similaridade entre palavras e da extensao da unidade textual ensinada sobre o desenvolvimento de leitura recombinativa. No Experimento 1 universitarios aprenderam relacoes condicionais entre pseudopalavras ditadas e impressas que diferiam das incorretas em 25% ou 75% dos elementos. No Experimento 2 outros universitarios aprenderam a relacionar letras ou silabas ditadas as correspondentes modalidades impressas e subsequentemente aprenderam relacoes envolvendo pseudopalavras. A aquisicao das discriminacoes foi mais rapida na Condicao Diferenca 75%; a leitura recombinativa dependeu da quantidade de palavras ensinadas (Exp.1). A leitura foi mais precisa apos a aprendizagem de silabas, mas ocorreu mais recombinacao apos a aprendizagem de letras (Exp. 2). Combinar o ensino de palavras dissimilares e de unidades menores que a palavra pode acelerar a leitura recombinativa.