Trees with structure

We investigate M-trees, that is, trees with structure possible at each node or level. M is a mathematical structure such as a set or a Cartesian product. An extension of Pólya's theorem is proved which allows the number of M-trees for a given number of nodes to be counted. The special case of componential trees is investigated. Here M is a Cartesian product of 0's and 1's. A componential analysis is a componential tree of depth 1, that is, there is no hierarchy. We prove that for any componential tree there exists a componential analysis which makes the same predictions on a triad test of judged similarity. A brief empirical example is given, in which a componential tree is applied as a model of a sernantic domain.     

Sex role stereotyping in Australian television advertisements

Television has attracted considerable attention in recent years because of alleged bias in its sex-role content. Studies of television in Great Britain and the United States have generally fuelled concerns that the medium presents male and female characters in traditionally stereotyped ways. Comparatively little research has focused on the way men and women are depicted in other nations' television. Such analyses contribute towards a more comprehensive account of sex role stereotyping and to cross cultural investigation. The present study examined the portrayal of male and female characters in a sample of contemporary Australian television advertisements. A sample of evening commercials was analyzed using measures developed in North American and British work. Strong evidence of differences in the presentation of male and female characters was obtained, and the differences were consistent with those reported in studies of television content in the northern hemisphere. There is little reason to suppose that this area of Australian media is changing substantially in response to public debate. The implications of possible differences between nations in terms of sex role stereotyping in commercials are discussed.     

Predicting Undergraduate Condom Use with the Fishbein and Ajzen and the Triandis Attitude-Behavior Models: Implications for Public Health Interventions1

The present study used two social-psychological theories of attitude-behavior relationships to investigate condom use by college undergraduates. One purpose of the present research is to provide information for public health practitioners to better design theory-based interventions to reduce the incidence of STD's by increasing the use of condoms. Another purpose is to compare the relative usefulness of two attitude-behavior models in predicting condom use. The Fishbein and Ajzen theory of reasoned action (Ajzen, 1988; Fishbein & Ajzen. 1980) was compared with a version of Triandis' theory of attitude-behavior relations (Triandis, 1977). Of major interest was whether variables in this version of the Triandis model increased the explanatory power of the Fishbein and Ajzen model in the prediction of condom use intention and behavior. In addition, specific outcome beliefs and normative beliefs held by subjects were used to predict condom use. One hundred and ninety college undergraduates were given a questionnaire designed to measure the components of the two models. Three months after completing the questionnaire, subjects were contacted by phone to record the subject's frequency of condom use (if the subject reported having had intercourse) during the 3-month period between initial assessment and follow-up. In the prediction of intention to use a condom, results indicate that one variable from the Triandis model, personal normative beliefs, increases the explanatory power offered by the expectancy value and normative belief components of the Fishbein and Ajzen model. In the prediction of reported condom use during the 3-month follow-up period, two variables from the Triandis model—perceived susceptibility and AIDS fear—significantly increased the predictive power of the Fishbein and Ajzen model. Based on these results, the authors propose an alternative model to explain undergraduate condom use. The implications of these findings for public health interventions to encourage the use of condoms is discussed.     

Atypical development of language and social communication in toddlers with Williams syndrome

Williams syndrome (WS) is a genetic disorder which results in an uneven cognitive profile. Despite superior language compared to other syndromes in the phenotypic outcome, toddlers with WS are as delayed in their language onset and early linguistic development as are toddlers with other syndromes. The cause of this delay in WS is as yet unknown. In a series of experiments, we examined whether atypical socio‐interactive precursors to language could contribute to the explanation of the late language onset and atypical developmental pathways observed in WS. Experiment 1 showed that despite superficially good social skills, toddlers with WS were only proficient at dyadic interaction. They were impaired in triadic interaction, essential for the referential uses of language, and showed none of the correlations between socio‐interactive markers and language seen in the typical controls. Experiment 2 focused on the comprehension and production of referential pointing. Again, the WS group was impaired, despite vocabulary levels higher than those of typically developing controls. Finally, Experiment 3 examined fine motor skills. The WS lack of pointing could not be explained in terms of motor impairments, since the WS toddlers were proficient at fine motor control, such as the pincer grip. Overall, our data indicate that the early stages of WS language follow an atypical pathway. The findings challenge the frequent claims in the literature that individuals with Williams syndrome have preserved linguistic and social skills.     

The influence of teacher expectations on student achievement in physical education classes: Pygmalion revisited

The main purpose of this study was to explore the relation between teacher expectations and student achievement in physical education classes, in the light of three complementary hypotheses. Student achievement may confirm teacher expectations because these expectations create self‐fulfilling prophecies, create perceptual biases, or accurately predict, without influencing, student achievement (Jussim, 1989 ). Another purpose was to examine the mediating role played by students' perceived ability in the teacher expectancy process. Study data were obtained from 173 students and 7 teachers. Path analysis revealed that teacher expectations have weak self‐fulfilling effects, strongly predicted student achievement mainly because they are accurate, and have no biasing effects on teacher judgements. Results also show evidence concerning the role of partial mediator of perceived student ability in the confirmation process of teacher expectations. Copyright © 2002 John Wiley & Sons, Ltd.     

The behavioural treatment of sleep difficulties in children with an intellectual disability

Reinforcement, instruction giving, partner support strategies, bedtime routine, and standard extinction were taught to the parents of three boys (aged 5–10 years) with an intellectual disability and sleeping difficulties. Sleep was measured using sleep diaries and actigraphy, and daytime behaviour was monitored using diaries and direct observation. At referral, all children needed a parent present to fall asleep, two had co‐sleeping difficulties, and two had night waking difficulties. At post‐intervention, all children were falling asleep independently, co‐sleeping was eliminated for two children, and night waking was reduced in one child. An extinction burst was experienced by two children, with one family putting their child back to bed 259 times on the first night. Though one child still had night waking difficulties following intervention, actigraph recording demonstrated an improvement in his sleep quality. In addition to the children's independence, improvements were seen for sleep length, sleep latency, and morning wake time. However, improvements in daytime behaviour showed inconsistency across behaviours and settings. Improvement in sleep was maintained at a three month follow‐up. It was concluded that using extinction to address sleep problems in children with an intellectual disability is effective and approved of by parents, but any impact on daytime behaviour is equivocal. Copyright © 2002 John Wiley & Sons, Ltd.     

Relationship between bullying and scores on the Buss‐Perry Aggression Questionnaire among imprisoned male offenders

This study investigated the relationship between bullying and aggression among imprisoned male adult offenders. The participants were 70 imprisoned male offenders, who were classified using the Direct and Indirect Prisoner Behaviour Checklist (DIPC) as one of four ‘bully’ groups: pure bully, pure victim, bully/victim, or not involved. Participants also completed the Buss‐Perry Aggression Questionnaire (AQ), a measure of aggression and hostility. The majority of the prisoners reported behaviors indicative of bullying, with 42.9 percent classified in the bully/victim group and 12.9 percent as pure bullies. 15.7 percent of participants were classified as pure victims, while 28.6 percent did not report any involvement in bullying. Bully/victims scored higher than participants who were not involved in bullying on the Hostility scale and Total score of the AQ. A number of correlations were found between the AQ scores and number of bully behaviors perpetrated. These suggested there is an overlap between the constructs measured by the AQ and type of bullying behaviors perpetrated. The number of bullying behaviors experienced was only correlated with the Hostility scale. The results are discussed in terms of previous research and their implications for theory and practice. Aggress. Behav. 31:1–11, 2005. © 2005 Wiley‐Liss, Inc.