Sex differences in mathematical reasoning ability at age 13: their status 20 years later

Reported is the 20-year follow-up of 1,975 mathematically gifted adolescents (top 1%) whose assessments at age 12 to 14 revealed robust gender differences in mathematical reasoning ability. Both sexes became exceptional achievers and perceived themselves as such; they reported uniformly high levels of degree attainment and satisfaction with both their career direction and their overall success. The earlier sex differences in mathematical reasoning ability did predict differential educational and occupational outcomes. The observed differences also appeared to be a function of sex differences in preferences for (a) inorganic versus organic disciplines and (b) a career-focused versus more-balanced life. Because profile differences in abilities and preferences are longitudinally stable, males probably will remain more represented in some disciplines, whereas females are likely to remain more represented in others. These data have policy implications for higher education and the world of work.     

Cholinergic modulation of trace conditioning trained in serial compound: A developmental analysis

In four experiments the effects of serial compound conditioning on responding to a trace-conditioned CS were evaluated using a fear conditioning paradigm. The subjects were 18- and 25-day-old Sprague-Dawley rats, previously shown to exhibit little or no trace fear conditioning. Here, animals as young as 18 days of age were shown to be capable of trace conditioning between a visual CS1 and a shock US, provided the trace interval was filled with a non-target CS2 during serial conditioning trials (CS1-->CS2-->US). To explore cholinergic mechanisms involved in trace and serial conditioning, additional experiments assessed conditioned responding following pre-training administration of the muscarinic receptor antagonist scopolamine. Scopolamine produced a dose-dependent reduction in responding to the trace CS1, regardless of whether subjects were trained with standard trace (CS1-->trace interval-->US) or serial (CS1-->CS2-->US) trials. Responding to CS2 was unaffected by scopolamine. These data suggest that central cholinergic systems are functional in the young animals, but are not normally sufficiently activated by standard trace conditioning procedures. The results suggest that serial compound conditioning can promote trace conditioning in young rats, as it does in adults, perhaps by enhancing cholinergic activity during training. Implications for the late ontogenetic emergence of trace conditioning as it relates to maturation of neural pathways and their role in the potentiating effects of a gap filler are discussed.     

Intention in motor learning through observation

The purpose of this experiment was to assess whether learning an action through observation is enhanced by the intention to reproduce the observed behaviour. Two groups of participants observed a model practise a timing task and performed a 24-hour delayed retention test. Participants in the first group of observers were explicitly instructed that they would be required to execute the timing task that they had observed as accurately as possible during the delayed retention test. Observers in the second group were instructed that they would be required to describe as accurately as possible the behaviour that they had observed. A control group of participants, who did not observe the model, was also administered the delayed retention test. The results of the retention test indicated that absolute timing (parameterization) was learned by the observers to the same extent with or without intention to reproduce the task. Indeed, on the retention test absolute timing for the two groups of observers was as effective as that for the models. However, observing with an intention to reproduce the task was beneficial for learning the movement's relative timing structure. Results are discussed with respect to a potential mechanism by which intention enhances observation.     

Childhood maltreatment associated with adult personality disorders: findings from the Collaborative Longitudinal Personality Disorders Study

Adverse childhood experiences such as abuse and neglect are frequently implicated in the development of personality disorders (PDs); however, research on the childhood histories of most PD groups remains limited. In this multisite investigation, we assessed self-reported history of abuse and neglect experiences among 600 patients diagnosed with either a PD (borderline, schizotypal, avoidant, or obsessive-compulsive) or major depressive disorder without PD. Results indicate that rates of childhood maltreatment among individuals with PDs are generally high (73% reporting abuse; 82% reporting neglect). As expected, borderline PD was more consistently associated with childhood abuse and neglect than other PD diagnoses. However, even when controlling for the effect of borderline PD, other PD diagnoses were associated with specific types of maltreatment.     

Axis I and axis II disorders as predictors of prospective suicide attempts: findings from the collaborative longitudinal personality disorders study

This study examined diagnostic predictors of prospectively observed suicide attempts in a personality disorder (PD) sample. During 2 years of follow-up, 58 participants (9%) reported at least 1 definitive suicide attempt. Predictors that were examined include 4 PD diagnoses and selected Axis I diagnoses (baseline and course). Multivariate logistic regression analyses indicated that baseline borderline personality disorder (BPD) and drug use disorders significantly predicted prospective suicide attempts. Controlling for baseline BPD diagnosis, proportional hazards analyses showed that worsening in the course of major depressive disorder (MDD) and of substance use disorders in the month preceding the attempt were also significant predictors. Therefore, among individuals diagnosed with PDs. exacerbation of Axis I conditions, particularly MDD and substance use, heightens risk for a suicide attempt.     

Enhancing Training Efficiency and Effectiveness Through the Use of Dyad Training

The authors examined the effect of inserting observation practice and undirected dialog into the rest interval between practice trials on the learning of a complex task (stabilometer). Training protocols in which learners practice in pairs (dyads) result in increases in learning efficiency, but the critical issue is the effect on learning effectiveness. Three groups of participants (n = 12 in each group) practiced maintaining their balance on a stabilometer. One group practiced individually, and the other 2 groups practiced in dyads in which 1 performer practiced the task while the other observed. In the dyad-alternate condition, participants alternated between physical, observational, and dialog practice on each trial, whereas in the dyad-control condition, subjects completed all trials on 1 form of practice (either physical or observational practice) before engaging in the other form. The results indicated that the dyad-alternate group initially performed more poorly but quickly overtook the individual group, and the performance advantage of the dyad-alternate group was maintained on the delayed retention test. When the different forms of practice were performed consecutively, as in the dyad-control group, acquisition and retention performance was generally poorer than when they were alternated. Those results suggest that one can combine the benefits of physical practice, observation, and dialog between learners in an interactive way to produce an effective and efficient learning protocol.     

Influence of movement activities on shape recognition and retention.

Three groups of 4-yr.-old children were asked to complete a form perception assessment instrument prior to, 1 hr. after, and 1 wk. following a treatment. Group 1 participated in a movement-based form perception program, while Group 2 was instructed using a traditional classroom method. A third group which acted as control participated in unrelated movement activities. A repeated-measures analysis of variance gave a main effect of tests and an interaction of groups X tests. Group 2 displayed significantly higher performance on the posttest than Group 1; however, after 7 wk. the performance of Group 2 had decreased to a level below that of Groups 1 and 3, which remained stable.     

Shifts in attention demands and motor program utilization during motor learning

The relationship between changes in the level of motor program utilization and attention demand during the learning of a motor task was examined. The primary task involved an 86-cm horizontal arm movement which subjects attempted to complete coincident with the end of a 360 degrees sweep of a clock hand. A secondary task performed with the opposite limb required a rapid button press to an auditory probe stimulus presented at various temporal locations within each trial. Control subjects performed either the primary task or the secondary task alone, while experimental subjects performed both tasks in combination. Schmidt's (1972) index of preprogramming was used to measure the level of motor program utilization, while probe reaction time reflected the attention demand of the primary task. There was a stable level of motor programming over four consecutive days of practice (100 trials a day), but a general decrease in attention demand. Implications for an expansion of the concept of the motor program were discussed.     

CONSERVATION IN COMMUNITY SCHOOL CHILDREN FROM THE MILNE BAY AND MOROBE PROVINCES OF PAPUA NEW GUINEA

Three hundred and forty primary level boys and girls from the Milne Bay and Morobe Provinces of Papua New Guinea were tested for conservation of number, length, quantity, and area. Relationships observed between schooling, age, sex and conservation confirmed previous conclusions from work in Papua New Guinea about the importance of the first two of these variables for conservation. Comparisons between different language-culture groups suggested that explanations of any lag in achieving conservation in Papua New Guinean children must give attention to specific characteristics of children's environments since groups which were significantly superior performers on some tasks were significantly inferior on others.