Attention deficit disorder with hyperactivity and methylphenidate: The effects of dose and mastery level on children's learning performance

This investigation examined the relationship between methylphenidate (MPH) and the learning and recall of paired associations by children with attention deficit disorder with hyperactivity (ADDH). Forty-five children with ADDH were randomly assigned to one of three groups (novel, partial mastery, and mastery learning) that varied in the amount of previous learning of paired associations and participated in a double-blind, placebo-control, repeated-measures-across-dose (crossover) design. Each child received four doses of MPH (5 mg, 10 mg, 15 mg, and 20 mg) and a placebo in a random, counterbalanced sequence. The results indicated that both the rate of acquisition and accuracy in learning paired associations were significantly, but differentially, affected by MPH dose and the degree of learning mastery. The implications of these results for psychopharmacological research and the monitoring of psychostimulant effects on children's learning performance in academic settings are discussed.The authors wish to acknowledge and express their sincere appreciation to the graduate and undergraduate student members of the Children's Learning Clinic.     

Telescoping is not time compression: A model

A model of telescoping is proposed that assumes no systematic errors in dating. Rather, the overestimation of recent occurrences of events is based on the combination of three factors: (1) Retention is greater for recent events; (2) errors in dating, though unbiased, increase linearly with the time since the dated event; and (3) intrusions often occur from events outside the period being asked about, but such intrusions do not come from events that have not yet occurred. In Experiment 1, we found that recall for colloquia fell markedly over a 2-year interval, the magnitude of errors in psychologists' dating of the colloquia increased at a rate of .4 days per day of delay, and the direction of the dating error was toward the middle of the interval. In Experiment 2, the model used the retention function and dating errors from the first study to predict the distribution of the actual dates of colloquia recalled as being within a 5-month period. In Experiment 3, the findings of the first study were replicated with colloquia given by, instead of for, the subjects.     

Altering memory through recall: The effects of cue-guided retrieval processing

Three experiments were designed to investigate the influence of initial recall on memory by assessing delayed recall after different immediate cued-recall tests. In all experiments, subjects performed semantic and phonemic encoding tasks on a word list. The subjects then received a cued-recall test that cued the target using the same word as the context word in the encoding task, a test that cued the target with a word from the same level at which the target was encoded, a test that cued the target with a cue from a different level at which the target was encoded, or no immediate-recall test. One day later, the subjects performed a final cued-recall test in which the type of cue (semantic or phonemic) was varied. Consistently, delayed recall was facilitated primarily when the cue on the immediate test was from the same level as the cue on the delayed test. This pattern of facilitation suggests that immediate cued-recall produces an elaboration of an existing memory representation that is closely tied to the type of cue used on the immediate test.     

List of publications: Husserliana (also translations) and Phaenomenologica

List of publications: Husserliana (also translations) and Phaenomenologica     

A neuroscience model of stuttering

Using motor control systems analysis and a reductionist approach, we provide a unified model of stuttering. This model views stuttering as a momentary instability in a complex multiloop control system. The model predicts the temporal conditions under which this instability will occur. Furthermore, these temporal conditions account for the efficacy of fluency-evoking maneuvers, therapy, and the variability of speech output in stutterers.     

Behavioral correlates of developmental expressive language disorder

The association of behavior problems with preschool language disorders has been documented extensively. However, researchers have typically failed to differentiate subgroups of language-impaired children, to use observational data in documenting the behavior disorders, or to study children at the youngest ages. Using a multimodal assessment, this study examined parent-child interaction and behavior problems in a clearly defined subgroup of language-impaired children, those with developmental expressive language disorder (ELD). These children exhibit a delay in expressive language compared with receptive language and nonverbal cognitive skills. Subjects were identified and studied at the youngest age at which the disorder can be assessed. A group of ELD children, averaging 27 months of age, was contrasted with a group of normally developing children, matched for age, sex, and receptive language ability. Groups were compared on observed parent-child interactions as well as maternal responses on the Parenting Stress Index, the Eyberg Child Behavior Inventory, and a behavior-related structured interview. ELD children, when compared with normally developing children, exhibited higher levels of negative behavior and were perceived as different by their parents.Portions of these data were presented at the biennial meeting of the Society for Research in Child Development, Baltimore, April 1987, and at the annual meeting of the Society for Pediatrie Research, Anaheim, California, April 1987. This work has been supported by NIMH grant no. 1 R03 MH41603 to author Fischel, and by NICHD grant no. 1 ROI HD19245 to authors Whitehurst and Fischel. It has also been supported by grants of equipment from Commodore Business Machines, Inc., Koala Corporation, and NEC Telephones. We thank the Department of Pediatrics at the Nassau County Medical Center for the use of their facilities.     

The systematic misrepresentation of bilingual-crossed aphasia data and its consequences

The evidence from bilingual-crossed aphasia which has been used to support a bilingualism-right hemisphere effect for language representation and/or processing is critically reevaluated. Data gathered by the case survey method are shown to have been misrepresented in the literature. The argument based on a single group study of right-lesioned subjects is shown to rest upon a fundamental misinterpretation of those data. The consequences of such misrepresentation and misinterpretation as reflected in recent research are discussed.     

Memory for internally generated words in Alzheimer-type dementia: breakdown in encoding and semantic memory

The "generation effect" is a phenomenon in which words that are generated by the subject are remembered better than words which are read. The present experiments examined this effect in patients with mild-to-moderate dementia of the Alzheimer type (DAT), healthy elderly adults, and young adults under a variety of different encoding and retrieval conditions. Experiment 1 employed an intentional learning task with multiple study/test trials using the same list of words. While both the young and elderly adults exhibited higher recall for internally generated words than read words, the DAT patients failed to demonstrate the effect even after repeated exposures to the same stimulus list. Experiment 2 replicated this same pattern of results using an incidental learning paradigm with both recall and recognition tests. Various explanations as to why the DAT patients failed to show the generation effect were discussed with particular emphasis placed on the role of semantic memory and encoding failure.     

Response to commentaries on “A neurobiological model for near-death experiences”

This work has received financial support from FONDECYT (Project 1111-88). The authors also acknowledge the helpful comments of Dr. Bruce Cassels.