Predictors and outcomes of early motherhood in the Australian Longitudinal Study on Women's Health

Early motherhood is identified as a social problem, and having children at an early age is assumed to lead to psychological distress, welfare dependence and socioeconomic disadvantage. Analysis of responses from 9,689 young participants in the Australian Longitudinal Study on Women's Health was used to examine predictors and outcomes of early motherhood in Australia. Survey 1 (1996, aged 18 - 23) and Survey 2 (2000, aged 22 - 27), were used to categorize women as Childless, Existing Mothers (before Survey 1) and New Mothers (became mothers before Survey 2). Multivariate logistic regressions provided comparisons on sociodemographics, gynaecological variables, psychological wellbeing and health behaviours. Survey 1 data show that Existing Mothers experience socioeconomic disadvantages and unhealthy lifestyles. However, those who will go on to become mothers earlier than their peers already experience similar disadvantages. Further, the Survey 2 data show that, when these pre-existing disadvantages are controlled for, the additional deficits experienced by early mothers are relatively minor. Social disadvantage predisposes women to become mothers early, and to adopt unhealthy behaviours. However, young Australian women cope well with the challenges of early motherhood. In the longer term, unhealthy lifestyles and low education may lead to ill health and disadvantage, but early motherhood is not the initiator of this trajectory.     

A methodology for assessing the functions of emerging speech in children with developmental disabilities

An approach based on Skinner's (1957) theory of verbal behavior has been developed to understand and teach elementary communication skills to children with autism and developmental disabilities (Sundberg & Partington, 1998). However, few studies have directly examined the characteristics of emerging language in children with developmental disabilities. The purpose of this study was to develop and evaluate an assessment for identifying the elementary functions of vocal speech in children. Participants were 4 children with developmental disabilities, aged 6 years to 12 years, who exhibited at least one distinguishable vocal response (word or phrase) frequently in the natural environment. The assessment focused on three verbal operants delineated by Skinner (mand, tact, and intraverbal). One or more functions were identified for at least one vocal response of each child. Results suggested that this assessment would be useful for (a) evaluating Skinner's theory, (b) guiding decisions about language training for individual children, and (c) studying the nature of expressive language development in children with developmental disabilities.     

"I'm OK but you're not" and other peer-relational schemas: explaining individual differences in children's social goals

This study examined the links among 5th and 6th graders' (279 girls and 310 boys) self- and peer perceptions, social goals, and social behavior. Social goals mediated the effects of self- and peer perceptions on 3 types of behavior: proactive aggression, prosocial behavior, and withdrawal. In addition to their main effects (self-perception predicting variance in agentic goals, peer perception being related to communal goals), self- and peer perception interacted in influencing social goals; for instance, the effects of a positive view of oneself were different in the contexts of a positive versus a negative perception of peers. It is suggested that in order to predict children's social behavior more accurately, researchers should investigate children's dual perceptions of themselves and of their peers--that is, their peer-relational schemas--instead of assessing self-perception and peer perception in isolation from each other.     

Misperception of sleep can adversely affect daytime functioning in insomnia

This experiment was designed to investigate the relationship between subjective perception of sleep and daytime processes in primary insomnia. Twenty-two individuals with primary insomnia received positive or negative feedback about their sleep, immediately on waking, on three consecutive mornings. The positive feedback was that last night's sleep was good quality. The negative feedback was that last night's sleep was poor quality. Objective sleep on each of the three nights was estimated by actigraphy and did not differ across the three nights or the two feedback conditions. Negative feedback (based on 32 nights of data) was associated with more negative thoughts, sleepiness, monitoring for sleep-related threat, and safety behaviours during the day, relative to positive feedback (based on 34 nights of data). These results indicate that the impaired daytime functioning reported by insomnia patients is maintained, at least in part, by subjective perception of sleep.     

Adult age and digit symbol substitution performance: a meta-analysis

This article reports the results of a meta-analysis of the effects of age, education, and estimated year of measurement on scores from the Wechsler Adult Intelligence Scale and the Wechsler Adult Intelligence Scale-Revised Digit Symbol Substitution Test. Analysis of effect sizes for age reported in 141 studies published between 1986 and 2002 indicated a mean standardized difference of -2.07. Age accounted for 86% of the variance in a regression model using age, education, and year submitted as predictors of Digit Symbol scores. There was no association between years of education or year submitted and Digit Symbol scores for younger adults or older adults.     

Age and responding-hand related changes in performance of neurologically normal subjects on the line-bisection and chimeric-faces tasks

This study investigated age and responding-hand (left, right, and bimanual) related changes in visuospatial attention. Two tasks were completed by 107 neurologically normal right-handed subjects ranging in age from 5 to 70 years and distributed across four age groups. Task-specific differences between groups were apparent. In the line-bisection task, the younger and older groups displayed symmetrical neglect while the young and middle groups displayed pseudoneglect. In the chimeric-faces task the leftward bias was less pronounced in the older group and more susceptible to responding-hand effects in the middle and older groups. Whilst results, especially those of the bimanual method, provided strong support for an activation model, they imposed an age limitation on its appropriateness as an explanation for performance on the chimeric-faces task. Results are discussed as reflecting changes in the corpus callosum and right hemisphere.     

Charpentier (1891) on the size—weight illusion

This paper offers background for an English translation of an article originally published in 1891 by Augustin Charpentier (1852–1916), as well as a summary of it. The article is frequently described as providing the first experimental evidence for the size—weight illusion. A comparison of experiments on the judged heaviness of lifted weights carried out by Weber (1834) and by Charpentier (1891) supports the view that Charpentiers work deserves priority; review of other experimental studies on the size-weight illusion in the 1890s suggests that the idea that the illusion depended on “disappointed expectations,” especially with respect to speed of lift, became dominant almost immediately following the publication of Charpentiers paper. The fate of this and other ideas, including “motor energy,” in 20th-century research on the illusion is briefly described.     

Probability: A new logico-semantical approach

This approach does not define a probability measure by syntactical structures. It reveals a link between modal logic and mathematical probability theory. This is shown (1) by adding an operator (and two further connectives and constants) to a system of lower predicate calculus and (2) regarding the models of that extended system. These models are models of the modal systemS ₅ (without the Barcan formula), where a usual probability measure is defined on their set of possible worlds. Mathematical probability models can be seen as models ofS ₅.     

The effect of movement amplitude and target diameter on reaction time: comments on Siegel (1977)

Siegel's (1977) interpretation that his reaction time results were solely a function of response factors (movement amplitude and target diameter) was discussed and criticized. It was argued that Siegel's interpretation was inappropriate because stimulus factors (eccentric and visual angle) and response factors were confounded. It was also argued that the surprising U-shaped relation between reaction time and movement amplitude was probably the result of the confounding between stimulus and response factors.     

The learning of programmed- and feedback- based processes controlling the production of a positioning response in two dimensions

Two experiments were conducted to investigate the learning of the programmed- and feedback-based processes controlling the production of a slow, self-paced positioning response in two dimensions (direction and extent) in the horizontal plane. Both experiments had two phases: an acquisition phase of 60 trials with KR, followed by a KR withdrawal phase of 20 trials. In Experiment 1, one group (N=15) had visual feedback about the ongoing movement and the other group (N=15) did not. In Experiment 2, one group (N=15) practiced initiating the response in the criterion direction and moving the criterion extent, whereas, the other group (N=15) practiced initiating the response in the criterion direction and moving randomly varied extents. The results of Experiment 1 indicated that the learning of a programmed-based process is a gradually acquired freedom from visual feedback. Experiment 2 revealed that a programmed-based process can be learned independent of a feedback-based process.