Intellectual development within transracial adoptive families: retesting the confluence model

The confluence model of intellectual development was estimated for a within-family sample of 321 children from 101 transracial adoptive families. Mental ages of the children and their parents, as well as birth or adoption intervals, were used in a nonlinear least-squares estimation procedure to obtain children's predicted mental ages. Contrary to an earlier report using these data, the confluence model performed quite well, accounting for up to 50% of the variance in mental age. When the relationship between chronological and mental age was taken into account, the predictive power of the model was reduced but not eliminated. The confluence model was also fitted separately to various subsamples. The model generated a good fit to the data from both biological and adopted children and fit the data from early-adopted children much better than the data from later-adopted children. Both findings were taken as evidence that the confluence model provides an environmental account of intellectual development within the family.     

Masculinity and femininity in twin children: genetic and environmental factors

Genetic and environmental origins of individual differences in masculine and feminine personality attributes were investigated in a sample of 38 monozygotic and 32 dizygotic twin pairs (total N = 140) during pre- and early adolescence. Self-report measures of both masculine and feminine characteristics were obtained for each child using 2 standardized instruments: the Children's Personality Attributes Questionnaire (CPAQ) and the Adolescent Self-Perception Inventory (ASPI). Multivariate biometrical analyses revealed significant genetic influences in all measures, accounting for 20%-48% of the observed variation in each. Environmental influences, which explained the remaining 52%-80% of variance in masculinity and femininity, were apparently specific to each individual and not shared by members of the same twin pair. The results underscore the importance of considering both genetic and environmental factors in gender-role development, particularly in studies of family resemblance.     

The Effects of Information and Feedback on Teachers’ Classroom Behaviour and Students’ Academic Engaged Time

Research has shown a positive relationship between academic engaged time (AET), academic learning time (ALT) and student achievement. Previous work has reported a relatively non‐intrusive, cost‐effective method for increasing AET in the classroom involving the presentation of research information followed by feedback to teachers of students’ AET in their classes. This study aimed to replicate these findings in a primary school setting and to establish what effects the information plus feedback had on teachers’ instructional behaviours which have been found to correlate with students’ AET and ALT. In addition, we looked at the effects of more precise feedback based on students’ task difficulty measures. The results provided strong support for the utility and efficacy of information plus feedback as a method for increasing student AET and ALT and for enabling teachers to change their instructional behaviours in the direction of published research findings.     

A conceptual overview of the regression discrepancy model for evaluating severe discrepancy between IQ and achievement scores

A conceptual overview of the Regression Discrepancy Model (RDM) for determining severe discrepancy between IQ and achievement scores is presented in order to enhance understanding of the model without the use of the complex mathematical equations that constitute the model. The six specific goals of the RDM are identified, and figures illustrate the manner in which the model accomplishes each goal. Figures are also provided from a RDM computer output showing the basic outcomes of the model. Advantages and disadvantages of the RDM are discussed to further promote understanding of the model.     

Concept learning by pigeons: Matching-to-sample with trial-unique video picture stimuli

Pigeons were trained to match-to-sample with several new methodologies: a large number of stimuli, computer-drawn color picture stimuli, responses monitored by a computer touch screen, stimuli presented horizontally from the floor, and grain reinforcement delivered onto the picture stimuli. Following acquisition, matching-to-sample concept learning was assessed by transfer to novel stimuli on the first exposure to pairs of novel stimuli. One group (trial-unique), trained with 152 different pictures presented once daily, showed excellent transfer (80% correct). Transfer and baseline performances were equivalent, indicating that the matching-to-sample concept had been learned. A second group (2-stimulus), trained with only two different pictures, showed no evidence of transfer. These results are discussed in terms of the effect of numbers of exemplars on previous failures to find concept learning in pigeons, and the implications of the positive finding from this experiment on abstract concept learning and evolutionary cognitive development.     

Persuasive communication: A theoretical model for changing the attitude of preservice elementary teachers toward metric conversion

This study was based on Hovland's four-part statement, “Who says what to whom with what effect,” the rationale for persuasive communication, a theoretical model for modifying attitudes. Part I was a survey of 139 perservice elementary teachers from which were generated the more credible characteristics of metric instructors, a central element in the “who” component of Hovland's model. They were: (1) background in mathematics and science, (2) fluency in metrics, (3) capability of thinking metrically, (4) a record of excellent teaching, (5) previous teaching of metric measurement to children, (6) responsibility for teaching metric content in methods courses and (7) an open enthusiasm for metric conversion. Part II was a survey of 45 mathematics educators where belief statements were synthesized for the “what” component of Hovland's model. It found that math educators support metric measurement because: (1) it is consistent with our monetary system; (2) the conversion of units is easier into metric than English; (3) it is easier to teach and easier to learn than English measurement; there is less need for common fractions; (4) most nations use metric measurement; scientists have used it for decades; (5) American industry has begun to use it; (6) metric measurement will facilitate world trade and communication; and (7) American children will need it as adults; educational agencies are mandating it. With the “who” and “what” of Hovland's four-part statement defined, educational researchers now have baseline data to use in testing experimentally the effect of persuasive communication on the attitude of preservice teachers toward metrication.