Perception of cliff swallow calls by birds (Hirundo pyrrhonota and Sturnus vulgaris) and humans (Homo sapiens).

We tested for species differences in the perception of the cliff swallow chick begging call. One cliff swallow (Hirundo pyrrhonota), 3 European starling (Sturnus vulgaris), and 3 human (Homo sapiens) subjects were trained on go-no-go or repeating background tasks to discriminate between all possible stimulus pairs, measured by percentage of correct response and latency. We used multidimensional scaling to convert the similarity measures into a 2-dimensional map for each subject. Most of the maps were significantly correlated in Dimension 1 but not in Dimension 2. A cluster analysis separated bird and human maps. To identify the most important acoustic cues for each subject, we regressed the coordinates of each dimension on acoustic variables measured from the stimuli. For all subjects, center frequency was Dimension 1. Different acoustic cues were associated with Dimension 2, with agreement only on bandwidth, by the cliff swallow and 1 starling.     

Generalized oddity performance in preschool children: a bimodal training procedure

Oddity performance requires relational discriminative responding, which typically is difficult to establish in children with MAs below five. In Experiment 1, a combination intrasubject reversal and multiple baseline across subjects design was used to establish the internal validity of a bimodal intervention in establishing generalized oddity performance. Six of seven children demonstrated oddity responding when presented with stimuli that instantiated the oddity relation in the visual and auditory modalities simultaneously. Oddity performance was evaluated with both reversal assessments and assessments with new sets of stimuli. The newly acquired oddity performance was durable; the six children continued to respond discriminatively when returned to a visual-only task on which they previously had been unsuccessful. Utilizing a reversal assessment more stringent than that of Experiment 1, Experiment 2 replicated this effect. The present studies are the first to demonstrate the utility of bimodal training in establishing oddity performance. The bimodal procedure is discussed with respect to the theoretical positions of Gibson, Dinsmoor, and Dixon.     

Do Social Connections and Hope Matter in Predicting Early Adolescent Violence?

We tested relationships between social connections, hope, and violence among young adolescents from socially distressed urban neighborhoods, and examined whether relationships between adolescents' family and school connectedness and violence involvement were mediated by hopefulness. Data were from middle school students involved in the Lead Peace demonstration study. The sample (N = 164) was 51.8% female; 42% African American, 28% Asian, 13% Hispanic, and 17% mixed race or other race; average age was 12.1 years; 46% reported physical fighting in the past year. In multivariate models, parent-family connectedness was protective against violence; school connectedness was marginally protective. Hopefulness was related to lower levels of violence. The relationship between school connectedness and violence was mediated by hopefulness; some evidence for mediation also existed in the family-parent connectedness and violence relationship. Findings warrant continued exploration of hopefulness as an important protective factor against violence involvement, and as a mediator in relationships between social connections and violence involvement.     

A Device for Studies in Weight Discrimination

Within-Ss 2×3 factorial design, with two methods—recall (REC) and anticipation (ANT)—and three levels of list difficulty, was used for testing the hypothesis that ANT is superior to REC only if the learning task is comparatively difficult. Each of 20 male university students learned, both by the methods of REC and ANT, pairs of 10 words and digits (WD), eight CVCs of moderate and six CCCs of low association values. Analysis of variance, except for the main effect of method, yielded high significance for all the main effects and interactions. In learning paired-associate lists for comparatively easier tasks (WD and CVC lists), no significant difference was found between the two methods. For CCC pairs, however, a significant difference was found (t = 2.50, p < .02), which supported the hypothesis. A tentative modification was suggested in W. K. Estes's theory of reinforcement in human learning.     

Classroom applications of stimulus equivalence technology

We review basic concepts and methods of stimulus equivalence research and suggest applications in teaching rudimentary language arts skills in the classroom. We describe methods of establishing equivalence-based networks of matching-to-sample, writing, and naming performances. The methods may be used as a supplement to classroom instruction to assess whether standard curriculum-based approaches establish such integrated networks. Methods derived from equivalence research may be useful for remediation when traditional teaching approaches fail. Recent research suggests that direct focus on spelling performances may be required if entire networks of language arts skills are to be acquired. In addition, the equivalence relations themselves may require concentrated teaching in some children.