Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.     

Treating Hypochondriasis with Interpersonal Psychotherapy

The treatment of hypochondriacal patients can be conceptualized as taking one of three approaches. These typically address one of the following questions: 1) “Should the patient be preoccupied?” 2) “Why is the patient preoccupied?” 3) “What are the interpersonal consequences of being preoccupied?” Interpersonal Psychotherapy (IPT) is specifically designed to address the last of these questions. IPT focuses on understanding the patient’s real distress, exploring the patient’s maladaptive communications, and modifying those communications so that others are more able to meet the patient’s attachment needs. With a focus on communication in a time-limited frame, fostered by a strong collaborative relationship, IPT appears to be an effective method of reducing hypochondriacal behavior.     

Effect of stimulant medication on lower extremity response time of boys with attention deficit hyperactivity disorder

Children with attention deficit hyperactivity disorder (ADHD) have been labeled as "inefficient movers"; however, little research has examined the effect of stimulant medication on lower extremity movements. 16 boys, 11 to 13 years old, with ADHD performed a lower-limb choice-response time task, both on and off medication. When nonmedicated, children had significantly slower reaction times to all three targets and significantly slower movement times for the contralateral and midline movements. For both conditions, children had significantly faster movement time when using the right leg than the left leg. These findings suggest that movement characteristics of children with ADHD are different under medicated and nonmedicated situations.     

A conceptual and psychometric framework for distinguishing categories and dimensions

An important, sometimes controversial feature of all psychological phenomena is whether they are categorical or dimensional. A conceptual and psychometric framework is described for distinguishing whether the latent structure behind manifest categories (e.g., psychiatric diagnoses, attitude groups, or stages of development) is category-like or dimension-like. Being dimension-like requires (a) within-category heterogeneity and (b) between-category quantitative differences. Being category-like requires (a) within-category homogeneity and (b) between-category qualitative differences. The relation between this classification and abrupt versus smooth differences is discussed. Hybrid structures are possible. Being category-like is itself a matter of degree; the authors offer a formalized framework to determine this degree. Empirical applications to personality disorders, attitudes toward capital punishment, and stages of cognitive development illustrate the approach.     

Updating target location at the end of an orienting saccade affects the characteristics of simple point-to-point movements

Six results are reported. (a) Reaching accuracy increases when visual capture of the target is allowed (e.g., target on vs. target off at saccade onset). (b) Whatever the visual condition, trajectories diverge only after peak acceleration, suggesting that accuracy is improved through feedback mechanisms. (c) Feedback corrections are smoothly implemented, causing the corrected and uncorrected velocity profiles to exhibit similar shapes. (d) Initial kinematics poorly predict final accuracy whatever the condition, indicating that target capture is not the only critical input for feedback control. (e) Hand and eye final variability are unrelated, suggesting that gaze direction is not a target signal for arm control. (f) Extent errors are corrected without modification of movement straightness; direction errors cause path curvature to increase. Together these data show that movements with straight paths and bell-shaped velocity profiles are not necessarily ballistic.     

Perception of visual speed while moving

During self-motion, the world normally appears stationary. In part, this may be due to reductions in visual motion signals during self-motion. In 8 experiments, the authors used magnitude estimation to characterize changes in visual speed perception as a result of biomechanical self-motion alone (treadmill walking), physical translation alone (passive transport), and both biomechanical self-motion and physical translation together (walking). Their results show that each factor alone produces subtractive reductions in visual speed but that subtraction is greatest with both factors together, approximating the sum of the 2 separately. The similarity of results for biomechanical and passive self-motion support H. B. Barlow's (1990) inhibition theory of sensory correlation as a mechanism for implementing H. Wallach's (1987) compensation for self-motion.