Sea lions and equivalence: expanding classes by exclusion

Experiments have shown that human and nonhuman subjects are capable of performing new arbitrary stimulus-stimulus relations without error. When subjects that are experienced with matching-to-sample procedures are presented with a novel sample, a novel comparison, and a familiar comparison, most respond by correctly selecting the novel comparison in the presence of the new sample. This exclusion paradigm was expanded with two California sea lions that had previously formed two 10-member equivalence classes in a matching-to-sample procedure. Rather than being presented with a novel sample on a given trial, the sea lions were presented with a randomly selected familiar member of one class as the sample. One of the comparisons was a randomly selected familiar member of the alternative class, and the other was a novel stimulus. When required to choose which comparison matched the sample, the subjects reliably rejected the familiar comparison, and instead selected the unfamiliar one. Next, the sea lions were presented with transfer problems that could not be solved by exclusion; they immediately grouped the new stimuli into the appropriate classes. These findings show that exclusion procedures can rapidly generate new stimulus relations that can be used to expand stimulus classes.     

Long-term memory for concepts in a California sea lion (<Emphasis Type="Italic">Zalophus californianus</Emphasis>)

An adult California sea lion (Zalophus californianus) with extensive experience in performing discrimination learning tasks was tested to evaluate her long-term memory for two previously learned concepts. An associative concept, that of equivalence classification, was retested after a retention interval of approximately 1 year. The sea lion had originally shown emergent equivalence classification with nonsimilarity-based classes of stimuli in a simple discrimination repeated-reversal procedure as well as in a matching-to-sample procedure. The 1-year memory test revealed no decrement in classification performance in either procedure. A relational concept, that of generalized identity matching, was retested after approximately 10 years. The sea lion had originally received trial-and-error exemplar training with identity matching-to-sample problems prior to transferring the concept to novel stimulus configurations. In the 10-year memory test, the sea lion immediately and reliably applied the previously established identity concept to familiar and novel sets of matching problems. These are the first reports of long-term conceptual memory in a nonprimate species. The experimental findings are consistent with a variety of observations of sea lions in natural settings, which indicate that natal sites, feeding areas, and individuals may be remembered over long periods of time. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/s10071-002-0153-8. On that page (frame on the left side), a link takes you directly to the supplementary material. Electronic Publication     

Relational frame theory and Skinner's Verbal Behavior: A possible synthesis

The current article suggests a possible synthesis of Skinner's (1957) treatment of verbal behavior with the more recent behavioral interpretation of language known as relational frame theory. The rationale for attempting to combine these two approaches is first outlined. Subsequently, each of the verbal operants described by Skinner is examined and subjected to a relational frame analysis. In each case, two types of operants are identified; one based on direct contingencies of reinforcement and the other based on arbitrarily applicable relational responding. The latter operants are labeled verbal because they can be distinguished from other forms of social behavior, and they appear to possess the symbolic or referential qualities often ascribed to human language. By applying relational frame theory to Skinner's verbal operants, we aim to contribute towards the development of a modern behavior-analytic research agenda in human language and cognition.     

Some neglected contributions of Wilhelm Wundt to the psychology of memory

Wilhelm Wundt, whose name is rarely associated with the scientific study of memory, conducted a number of memory experiments that appear to have escaped the awareness of modern cognitive psychologists. Aspects of Wundt's system are reviewed, particularly with respect to his experimental work on memory. Wundt investigated phenomena that would fall under the modern headings of iconic memory, short-term memory, and the enactment and generation effects, but this research has been neglected. Revisiting the Wundtian perspective may provide insight into some of the reasons behind the historical course of memory research and in general into the progress of science in psychology.     

Development of upper limb proprioceptive accuracy in children and adolescents

This study was designed to determine differences in the proprioceptively guided movements of children (8-10 years) and adolescents (16-18 years). Participants were blindfolded and asked to actively match passively determined target positions of the elbow joint under three matching conditions. Overall, children were less accurate than adolescents in all matching tasks and utilized different kinematic strategies for making the matching movements. Specifically, children made larger absolute errors and utilized matching movements which, compared to adolescents, were of shorter duration and less irregular in terms of their velocity profiles. An assessment of limb asymmetry was also performed revealing a non-dominant arm matching advantage but only for children and only in the task requiring interhemispheric transfer of a memory-based model of limb position. The proprioceptive differences observed in this study are likely the result of experience-driven refinement in the utilization of somatosensory feedback throughout childhood and into adolescence.     

One-year-olds comprehend the communicative intentions behind gestures in a hiding game

This study explored infants' ability to infer communicative intent as expressed in non-linguistic gestures. Sixty children aged 14, 18 and 24 months participated. In the context of a hiding game, an adult indicated for the child the location of a hidden toy by giving a communicative cue: either pointing or ostensive gazing toward the container containing the toy. To succeed in this task children had to do more than just follow the point or gaze to the target container. They also had to infer that the adult's behaviour was relevant to the situation at hand - she wanted to inform them that the toy was inside the container toward which she gestured. Children at all three ages successfully used both types of cues. We conclude that infants as young as 14 months of age can, in some situations, interpret an adult behaviour as a relevant communicative act done for them.     

The Relative Contribution of Sibling Deviance and Peer Deviance in the Prediction of Substance Use Across Middle Childhood

This study investigated the quality of sibling relationships and sibling deviancy in a sample of children at-risk for substance use and antisocial behavior. Based on a history of empirical and theoretical models suggesting strong associations between children's development in the context of relationships and the emergence of delinquency and drug use, this research extends previous efforts by including sibling relationships in this developmental model, linking siblings with later substance use. Sibling relationship quality as well as peer deviance were examined using a multirater, multimethod assessment procedure. We tested 3 constructs (deviancy, warmth, and conflict) related to sibling behavior. Only sibling deviance and peer deviance directly predicted substance use. When both sibling deviance and peer deviance were examined as predictors of changes in substance use over time, only sibling deviance was significant. Implications for the development of substance use behavior in middle childhood are discussed.     

An analysis of initial acquisition and maintenance of sight words following picture matching and copy cover, and compare teaching methods

This study compared the copy, cover, and compare method to a picture-word matching method for teaching sight word recognition. Participants were 5 kindergarten students with less than preprimer sight word vocabularies who were enrolled in a public school in the Pacific Northwest. A multielement design was used to evaluate the effects of the two interventions. Outcomes suggested that sight words taught using the copy, cover, and compare method resulted in better maintenance of word recognition when compared to the picture-matching intervention. Benefits to students and the practicality of employing the word-level teaching methods are discussed.     

Client-level predictors of adherence to MST in community service settings

This study examined the association of youth and family characteristics with therapist fidelity to an evidence-based treatment provided in real world practice settings. Participants were 233 families that reported on the 66 therapists organized into 16 teams in nine organizations providing multisystemic therapy (MST). Therapist adherence ratings were lower for youths referred for both criminal offenses and substance abuse than for youths referred either for substance abuse or status offenses, and was negatively associated with pretreatment arrests and school suspensions. Adherence ratings were positively associated with educational disadvantage and caregiver-therapist ethnic match and marginally positively associated with economic disadvantage. The findings suggest directions for future research on the implementation of evidence-based treatments in community settings.     

"... As you would have them do unto you": Does imagining yourself in the other's place stimulate moral action?

Philosophers, psychologists, and religious teachers have suggested that imagining yourself in another's place will stimulate moral action. The authors tested this idea in two different situations. In Experiment 1, participants had the opportunity to assign themselves and another research participant to tasks, with one task clearly more desirable than the other. Imagining oneself in the other's place did little to increase the morality (fairness) of the decision. A different form of perspective taking, imagining the other's feelings, increased direct assignment of the other to the desirable task, apparently due to increased empathy. In Experiment 2, participants confronted a different decision: either accept an initial task assignment that would give them highly positive consequences and the other participant nothing or change the assignment so they and the other would each receive moderately positive consequences. In this situation, imagining oneself in the other's place did significantly increase moral action.