Age differences in noise and variability of isometric force production.

This study examined whether age-related improvements observed in the motor performance of children result from a reduction of noise in the output of the sensori-motor system. Children ages 6, 8, and 10 years and young adults (N = 48, 12 per group) performed continuous, constant isometric force contractions with the index finger at four different force levels with and without visual feedback. The results revealed that: (a) performance improved with increases in age, (b) the force output signal exhibited increased irregularity and a more broadband frequency profile with increases in age under conditions with feedback, and (c) there were no age differences in the irregularity of the force signal and smaller age differences in the frequency profiles under conditions without feedback. It is proposed that the age-related enhancements in performance throughout childhood are primarily due to a more appropriate mapping of the organization of the sensori-motor system to the task constraints rather than to reduction of system noise.     

Life With a Partner with ADHD: The Moderating Role of Intimacy

Adult attention deficit and hyperactivity disorder (ADHD) manifests itself through a variety of symptoms, some of which affect not only occupational and recreational activities but also intimate relationships. Previous findings have focused on the effects of adult ADHD on intimacy and relationships from the ADHD diagnosed person’s point of view. However, spouses of people with ADHD are a neglected population with regard to the effects that ADHD has on their romantic relationships. Our aim was to assess the effects of being married to a spouse with ADHD on marital relationships, and the moderating role of intimacy. We compared healthy spouses of people with ADHD to healthy spouses of healthy adults (M?=?38.23, SD?=?4.78) in their degree of self-reported intimacy and marital satisfaction. Our findings indicate that spouses of individuals with ADHD report significantly lower intimacy and lower marital satisfaction compared to spouses of individuals without ADHD. Moreover, our findings indicate that spousal reports about their degree of intimacy mediate the relationships between their spouses’ ADHD and their marital satisfaction. Results are discussed in relation to the broad implications that adult ADHD has for romantic intimacy. Our research addresses healthy partners married to a spouse with ADHD, suggesting that living with a partner with ADHD behaviors is challenging. ADHD symptoms negatively affect various qualities in the person experiencing them, but of equal importance is the damage occurring to his or her spouse. Implications for future research and recommendations for clinical work are suggested.     

On Learning to Move Randomly

In 2 experiments, the authors examined whether and to what degree young adults can learn to produce random planar motion of the index finger or fingers. Three different types of information feedback were provided to the participants (N = 8 in each experiment) over up to 5 days of practice across the 2 experiments. The results from both experiments revealed that the participants produced a relatively low level of movement randomness in finger motion and that they did not learn through practice to enhance the stochastic properties of their movement under any feedback conditions. The findings provide further evidence that there are relatively tight constraints on the number of dimensions that are regulating single-limb planar motion and that those constraints are not susceptible to change through typical learning protocols.     

Early life events as discriminators of socialized and undersocialized delinquents

The relationship between early life events and the socialized and undersocialized dimensions of conduct disorder was investigated. Subjects were 40 incarcerated male delinquents and their mothers. The mothers were administered the Children's Life Events Questionnaire and the Developmental Questionnaire. Youths were administered the Adolescent Parent Relations Scale. The results indicated that the undersocialized delinquents had a greater number of stressful life events during their first 4 years of life than did the socialized delinquents. Discriminant function analysis indicated that stressful life events during the 2nd and 4th years were the most important predictors of membership in the undersocialized group. The discriminant function generated was able to classify 82.5% of the sample correctly. The remaining variables did not significantly discriminate the groups.