Motor timing deficits in community and clinical boys with hyperactive behavior: the effect of methylphenidate on motor timing

In a previous paper we showed that community children with hyperactive behavior were more inconsistent than controls in the temporal organization of their motor output. In this study we investigated: (1) various aspects of motor timing processes in 13 clinically diagnosed boys with attention deficit hyperactivity disorder (ADHD) who were compared to 11 community boys with hyperactive behavior and to a control group and (2) the effect of methylphenidate on the motor timing processes in the clinical group with ADHD in a double blind, cross-over, medication-placebo design, including 4 weeks of medication. The clinical group with ADHD, like the community group with hyperactivity, showed greater variability in sensorimotor synchronization and in sensorimotor anticipation relative to controls. The clinical group was also impaired in time perception, which was spared in the community group with hyperactivity. The persistent, but not the acute dose, of methylphenidate reduced the variability of sensorimotor synchronization and anticipation, but had no effect on time perception. This study shows that motor timing functions are impaired in both clinical and community children with hyperactivity. It is the first study to show the effectiveness of persistent administration of methylphenidate on deficits in motor timing in ADHD children and extends the use of methylphenidate from the domain of attentional and inhibitory functions to the domain of executive motor timing.     

The role of motion direction selective extrastriate regions in reading: a transcranial magnetic stimulation study

Why reading ability is correlated with motion processing ability is perplexing. Activity in motion direction processing regions (Area V5/MT+) was perturbed by means of repetitive transcranial magnetic stimulation (rTMS) to examine its effect on reading. A functional probe (significant shortening of the motion aftereffect) was used to identify Area V5/MT+. Right-handed participants (8 m, 8 f) received three 7.5 min blocks of rTMS, after which two phonological and one orthographic reading tasks were administered. Application of rTMS to Area V5/MT+ (as compared to a non-rTMS baseline) significantly decreased performance only during non-word naming. The pattern of naming errors and the absence of deficits on the second phonological task were not consistent with a role for Area V5/MT+ in phonological decoding. Instead, its role in reading may be limited to image stabilization and/or letter localization.     

Holding on to childhood language memory

While early language experience seems crucial for mastering phonology, it remains unclear whether there are lasting benefits of speaking a language regularly during childhood if the quantity and quality of speaking drop dramatically after childhood. This study explored the accessibility of early childhood language memory. Specifically, it compared perception and production of Korean speech sounds by childhood speakers who had spoken Korean regularly for a few years during childhood to those of two other groups: (1) childhood hearers who had heard Korean regularly during childhood but had spoken Korean minimally, if at all; and (2) novice learners. All three groups were enrolled in first-year college Korean language classes. Childhood speakers were also compared to native speakers of Korean to see how native-like they were. The results revealed measurable long-term benefits of childhood speaking experience, underscoring the importance of early language experience, even if such experience diminishes dramatically beyond childhood.     

Impasse-directed mediation with high conflict families in custody disputes

In this article we review current mediation models for resolving custody and visitation disputes and their success rates and identify the characteristics of a subpopulation with poor outcome: those parents who are in high conflict, ambivalent about separation, emotionally distressed, and limited in their capacity to protect their children. Based on an understanding of what creates impasses, and how children are affected, we present a new model of mediation for this subpopulation. Preliminary outcome data using this model with 80 families is reported. Implications for establishing a network of services for divorcing families are discussed.     

The Effects of Ratee Prototypicality on Rater Observation and Accuracy1

Social cognition theory asserts that perceivers (raters) assign stimulus persons (ratees) to social categories. These categories help the raters encode, store, and recall information. In a longitudinal design that represented a performance appraisal situation, this study examined the effects of information about a ratee's category membership on the amount of information that raters collected about the ratee prior to rating. One hundred fourteen subjects participated in three separate experimental sessions which spanned a 3-week time period. Among other tasks, subjects were required to rate a subordinate who was described in a manner which made it either difficult or easy to assign the subordinate to a social category. It was predicted and found that raters of ratees who were easily categoriezed spent less time observing the ratees' performance than raters of ratees who were less easily classified. Furthermore, results indicated that it was the effect of rater categorization on observation time that was critical to rating accuracy.     

A dissociative word-frequency X levels-of-processing interaction in episodic recognition and lexical decision tasks

The effects of levels-of-processing and word frequency were directly compared in three different memory tests. In the episodic recognition test, the subjects decided whether or not a word or a pronounceable nonword had been previously studied. In the two lexical decision tests with either pronounceable or unpronounceable nonwords as distractors, the subjects decided whether a test item was a word or a nonword. There were four main results: (1) in all three tests, reaction times (RTs) in response to studied words were faster if they had received semantic rather than rhyme processing during study; (2) in the episodic recognition test, RTs were faster for low- than for high-frequency words; in both lexical decision tests, RTs were faster for high- than for low-frequency words, though less so when the nonword distractors were unpronounceable; (3) prior study facilitated lexical decisions more in response to low- than to high-frequency words, thereby attenuating the word-frequency effect, but more so when the nonword distractors were pronounceable; (4) in the lexical decision test with pronounceable nonword distractors, relative to prior rhyme processing, prior semantic processing facilitated performance more for high- than for low-frequency words, whereas the opposite was the case in the episodic recognition test. Discussion focused on the relationship of these results to current views of the mechanisms by which (1) word frequency and depth of processing affect performance in implicit and explicit memory tests, and (2) repetition priming attenuates word-frequency effects for lexical decisions.     

Multiple access of homonym meanings: An artifact of backward priming?

A color-naming task was employed to determine whether multiple homonym meanings are accessed from the lexicon independently of context. Subjects heard sentences ending in homonyms, then, either 0 or 200 msec later, saw target words that were appropriately related, inappropriately related, or unrelated to the preceding homonym. Results supported the prediction that color-naming responses to both appropriate and inappropriate targets would be inhibited relative to unrelated targets at the 0-msec interstimulus delay. Within 200 msec, inappropriate targets were no longer inhibited, indicating that context had acted to select the appropriate meaning. The color-naming task is known to eliminate the possibility of backward priming; therefore, the multiple access effect obtained in this study cannot be an artifact of backward priming.     

Analyzing sequential relations in observational data: A practical guide

Many observational systems in basic and applied research produce a record of sequences of events over time. Within such observational systems, important information may be found in the frequency of the transitions between events that does not emerge in the typical researcher's focus on absolute event frequency. Indeed, if many behaviors are controlled by closely adjacent preceding events, then substantial prediction and control can be obtained through knowledge and manipulation of causal event transitions. A method for analyzing and testing sequential dependencies between events is proposed as part of an integrated package of computer-based data entry, storage, and analysis procedures. The mathematical portion of these techniques is based on the statistic, kappa,which is applicable to determining whether particular transitions among events differ from chance and whether particular transitions differ significantly across groups of subjects. Low-cost hardware and software to implement the proposed procedures are described.This work has been supported by Grant 1 RO1 HD19245-01A1 from the National Institute of Child Health and Human Development to the two senior authors and by grants of equipment from Commodore Computers, Inc., Koala Corporation, and NEC Telephones, Inc.     

Feature cues in probability learning: Data base information and judgment

Judgments of probabilistic events are often based partly on some information about past similar events. This study investigates the impact of summarized historical data termed a feature cue on performance in a cue probability learning task. Judges (n = 64) made 150 predictions of a criterion variable (Y_e) from a single cue variable (X). The feature cue variable (Z) provided judges with the “average past criterion” for the cue value on trial i, i.e., the conditional mean . Availability of the feature cue was varied with an AB-BA transfer design. Results demonstrate that the presence of the feature cue greatly imporved prediction achievement and accuracy. Under certain conditions, consistency and cue weighting were also improved by the feature cue aid. Although the feature cue value itself was not used as a prediction, it served as an anchor, around which judgments were dispersed. Implications for decision making with data base information are discussed.     

A pool of 1,086 words with unique two-letter fragments

Cognitive psychology is finding increasing use for the word fragment completion test, in which words have to be completed from a subset of their letters (e.g.,horizon from --r-z--). Researchers often try to restrict their fragments to those that can be completed with only one word, but this is difficult to do and probably never has been achieved. To help resolve this problem, a list is provided of 1,086 three- to eight-letter words, each of which is uniquely specified by a two-letter fragment, where uniqueness is defined on the basis of two sizable word collections.