Dissociation of explicit and implicit timing in repetitive tapping and drawing movements

Four experiments explored the hypothesis that temporal processes may be represented and controlled explicitly or implicitly. Tasks hypothesized to require explicit timing were duration discrimination, tapping, and intermittent circle drawing. In contrast, it was hypothesized that timing control during continuous circle drawing does not rely on an explicit temporal representation; rather, temporal control is an emergent property of other control processes (i.e., timing is controlled implicitly). Temporal consistency on the tapping and intermittent drawing tasks was related, and performance on both of these tasks was correlated with temporal acuity on an auditory duration discrimination task. However, timing variability of these 3 tasks was not correlated with timing variability of continuous circle drawing. These results support the hypothesized distinction between explicit and implicit temporal representations.     

Methylphenidate in treatment of adults with Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) can persist into adulthood with a continuation of the pattern of childhood psychopathology, cognition and functioning. Adult comorbidities include substance use disorders, antisocial personality disorder, anxiety, and depression. Studies have shown that as in children, methylphenidate treatment for adults can lead to a robust, dose-dependent improvement in ADHD symptoms. Future research is needed to evaluate the safety and efficacy of long-term treatment with methylphenidate (MPH).     

Minimal experience required for immediate-early gene induction in zebra finch neostriatum

We show that a single presentation of a zebra finch song, 2 s in duration, will induce an "immediate-early gene" response in the caudomedial neostriatum of zebra finches (Poephila guttata). Repetition of this stimulus 10 times is sufficient to induce a maximal increase in RNA and protein, detected 30 and 90 min later respectively. Thus very brief stimuli can set in motion a slow genomic process in the brain which takes hours to resolve. Immediate-early gene function is often considered in the context of a "feedback" model (i.e., to consolidate memories of the inducing event). However, based on the long lag observed here between initiation and full expression of the molecular response, we suggest an alternative, ethologically based, "feed-forward" model in which exposure to a novel or significant context triggers an increase in the efficiency of memory capture processes for subsequent experiences.     

Timing variability in circle drawing and tapping: probing the relationship between event and emergent timing

R. Ivry, R. M. Spencer, H. N. Zelaznik, and J. Diedrichsen (2002) have proposed a distinction between timed movements in which a temporal representation is part of the task goal (event timing) and those in which timing properties are emergent. The issue addressed in the present experiment was how timing in conditions conducive to emergent timing becomes established. According to what the authors term the transformation hypothesis, timing initially requires an event-based representation when the temporal goal is defined externally (e.g., by a metronome), but over the first few movement cycles, control processes become established that allow timing to become emergent. Different groups of participants (N = 84) executed either 1 timed interval, 4 timed intervals, or 2 timed intervals separated by a pause. They produced the intervals by either circle drawing, a task associated with emergent timing, or tapping, a task associated with event timing. Analyses of movement variability suggested that similar timing processes were used in the 2 tasks only during the 1st interval. Those results are consistent with the transformation hypothesis and lead to the inference that the transition from event-based control to emergent timing can occur rapidly during continuous movements.     

Types of high self-esteem and prejudice: how implicit self-esteem relates to ethnic discrimination among high explicit self-esteem individuals

There is increasing recognition that high self-esteem is heterogeneous. Recent research suggests that individuals who report having high self-esteem (i.e., have high explicit self-esteem) behave more defensively to the extent that they have relatively low implicit self-esteem. The current studies test whether individuals with high explicit self-esteem are more likely to discriminate ethnically, as a defensive technique, to the extent that they have relatively low implicit self-esteem. The results support this prediction. Among participants with high explicit self-esteem, all of whom were threatened by negative performance feedback, those with relatively low implicit self-esteem recommended a more severe punishment for a Native, but not a White, student who started a fist-fight. In Study 2, this pattern was not apparent for participants with relatively low explicit self-esteem.     

A laboratory school comparison of mixed amphetamine salts extended release (Adderall XR) and atomoxetine (Strattera) in school-aged children with attention deficit/hyperactivity disorder

Mixed amphetamine salts extended release (MAS XR; Adderall XR) and atomoxetine (Strattera) were compared in children 6 to 12 years old with attention deficit/hyperactivity disorder (ADHD) combined or hyperactive/impulsive type in a randomized, double-blind, multicenter, parallel-group, forced-dose-escalation laboratory school study. Primary efficacy measure was the SKAMP (Swanson, Kotkin, Agler, M-Flynn, and Pelham) behavioral rating scale. Changes in mean SKAMP deportment scores from baseline were significantly greater for MAS XR (n = 102) than for atomoxetine (n = 101) overall (-0.56 and -0.13, respectively; p < .0001) and at each week (p < .001). Adverse events were similar for both treatment groups. The extended time course of action and greater therapeutic efficacy of MAS XR suggests that it is more effective than atomoxetine in children with ADHD.     

Adolescent personality: a five-factor model construct validation

The purpose of this study was to investigate convergent and discriminant validity of the five-factor model of adolescent personality in a school setting using three different raters (methods): self-ratings, peer ratings, and teacher ratings. The authors investigated validity through a multitrait-multimethod matrix and a confirmatory factor analysis correlated trait, uncorrelated method model. With the exception of Emotional Stability, each analysis demonstrated similar patterns and together provided support for the convergent and discriminant validity of the five-factor model structure of adolescent personality. However, among the three raters, self-ratings of personality provided a comparatively weaker method for assessing adolescent personality. The influences of agreement between self and other raters are discussed in relation to contrast, perceiver, and target effects; expert observer effects; the degree of acquaintanceship; and the effect of the social context.     

Minority adolescents and substance use risk/protective factors: a focus on inhalant use

Despite the fact that inhalant use is a growing problem among youth in the United States, relatively little attention has been paid to the demographic and social factors related to its use. This study used data from a household survey of adolescents in Washington state, and found that race/ethnicity was a strong predictor of lifetime prevalence of inhalant use, with Native-American youth being particularly likely to use inhalants. Comparing the age at initiation of inhalant use to other legal and illegal substances, we found that cigarettes and inhalants showed the lowest age at initiation. We conducted logistic regressions on lifetime prevalence of inhalant use, and compared these models to other substances. In general, we found that attachment to parents. parents' drug use, and school attachment were strong predictors of lifetime use of marijuana, alcohol, and inhalants. However, while peer drug use was a strong predictor of marijuana and alcohol use, it was not a significant predictor of adolescents' use of inhalants. Our final set of analyses included inhalant use in regression models predicting other problem behaviors: these analyses demonstrated that inhalant use was a strong predictor of involvement in problem behavior.     

Affirmative action. Psychological data and the policy debates

The authors bring psychological research to bear on an examination of the policy of affirmative action. They argue that data from many studies reveal that affirmative action as a policy has more benefits than costs. Although the majority of pro-affirmative action arguments in the social sciences stress diversity, the authors' argument focuses on issues of merit. The merit-based argument, grounded in empirical studies, concludes that the policy of affirmative action conforms to the American ideal of fairness and is a necessary policy.