Internal evidence of bias in the PPVT-R for Anglo-American and Mexican-American children

This study examines item bias on Forms L and M of the Peabody Picture Vocabulary Test-Revised(PPVT-R) for a sample of Anglo-American and Mexican-American children. Analyses of variance (ANOVA) were employed to assess item bias as defined by items X ethnicity interactions. Follow-up analyses were performed using a Bonferroni-type procedure on individual item contrasts. Bias as measured by differences in item difficulty was found in both groups; however, there was no clear pattern of items that were more difficult for either group. The small number of items that were more difficult for one ethnic group than for the other, coupled with the high reliability of performance overall for both groups, suggest that bias in content of the PPVT-R is minimal.     

Influence of children's positive self-perceptions on donating behavior in a naturalistic setting

The present study investigated the effects of self-perceptions on the donating behavior of 43 fourth-grade students. The children had two opportunities to donate gum to another class. Half of the students received feedback after the first donation period indicating that they were particularly generous. These children subsequently gave more than children in the control group (p<.05). Sociometric measures indicated that the perceptions children had of themselves and others were related to donating. The results were similar for both males and females. Children process new information into their cognitive systems. The resulting cognitions help guide future behaviors.     

Restraint and Cancellation: Multiple Inhibition Deficits in Attention Deficit Hyperactivity Disorder

We used variations of the stop signal task to study two components of motor response inhibition—the ability to withhold a strong response tendency (restraint) and the ability to cancel an ongoing action (cancellation)—in children with a diagnosis of attention deficit hyperactivity disorder (ADHD) and in non-ADHD controls of similar age (ages 7–14 years). The goal was to determine if restraint and cancellation were related and if both were deficient in ADHD. The stop signal task involved a choice reaction time task (go task) which required a rapid response. The demand for inhibitory control was invoked through the presentation of a stop signal on a subset of go trials which required that the ongoing response be suspended. The stop signal was presented either concurrently with the go signal (restraint version) or after a variable delay (cancellation version). In Study 1, we compared ADHD and control children on the cancellation version of the stop task; in Study 2, we compared ADHD and controls on the restraint version. In Study 3, a subset of ADHD and control participants completed both tasks so that we could examine convergence of these dimensions of inhibition. Compared to control participants, ADHD participants showed a deficit both in the ability to cancel and to restrain a speeded motor response. Performance on the restraint version was significantly correlated with performance on the cancellation version in controls, but not in ADHD participants. We conclude that ADHD is associated with deficits in both restraint and cancellation subcomponents of inhibition.     

Participation: A Religious Worldview

This essay is an experimental project. It proposes that the theme of participation issues in an insightful, distinctive, comprehensive, and coherent interpretation of human experience. My personal history is a test case.     

The roles of delay and retroactive interference in retrieval-induced forgetting

When subjects study items from different categories and then repeatedly retrieve some of the items from some of the categories, retrieval practice typically improves recall of the practiced items but impairs recall of related but unpracticed items, relative to control items from unpracticed categories. Here, we report the results of three experiments, in which we examined practiced and unpracticed items’ delay-induced forgetting (Exp. 1) and their susceptibility to retroactive interference (Exps. 2 and 3). Control items showed the expected memory impairment after longer delay between practice and test and in the presence of retroactive interference. In contrast, both the practiced and the related unpracticed items showed hardly any forgetting under these conditions. The findings are consistent with the results from recent testing-effect studies, which have reported reduced delay-induced forgetting and reduced susceptibility to interference for retrieval-practiced items, and generalize the results to related unpracticed items. The findings are discussed with respect to the inhibitory and noninhibitory accounts of retrieval-induced forgetting, as well as the possible role of selective segregation processes, which may be induced by retrieval practice.     

Processing of audiovisually congruent and incongruent speech in school‐age children with a history of specific language impairment: a behavioral and event‐related potentials study

Previous studies indicate that at least some aspects of audiovisual speech perception are impaired in children with specific language impairment (SLI). However, whether audiovisual processing difficulties are also present in older children with a history of this disorder is unknown. By combining electrophysiological and behavioral measures, we examined perception of both audiovisually congruent and audiovisually incongruent speech in school‐age children with a history of SLI (H‐SLI), their typically developing (TD) peers, and adults. In the first experiment, all participants watched videos of a talker articulating syllables ‘ba’, ‘da’, and ‘ga’ under three conditions – audiovisual (AV), auditory only (A), and visual only (V). The amplitude of the N1 (but not of the P2) event‐related component elicited in the AV condition was significantly reduced compared to the N1 amplitude measured from the sum of the A and V conditions in all groups of participants. Because N1 attenuation to AV speech is thought to index the degree to which facial movements predict the onset of the auditory signal, our findings suggest that this aspect of audiovisual speech perception is mature by mid‐childhood and is normal in the H‐SLI children. In the second experiment, participants watched videos of audivisually incongruent syllables created to elicit the so‐called McGurk illusion (with an auditory ‘pa’ dubbed onto a visual articulation of ‘ka’, and the expectant perception being that of ‘ta’ if audiovisual integration took place). As a group, H‐SLI children were significantly more likely than either TD children or adults to hear the McGurk syllable as ‘pa’ (in agreement with its auditory component) than as ‘ka’ (in agreement with its visual component), suggesting that susceptibility to the McGurk illusion is reduced in at least some children with a history of SLI. Taken together, the results of the two experiments argue against global audiovisual integration impairment in children with a history of SLI and suggest that, when present, audiovisual integration difficulties in this population likely stem from a later (non‐sensory) stage of processing.     

Retrieval practice can eliminate list method directed forgetting

It has recently been shown that retrieval practice can reduce memories’ susceptibility to interference, like retroactive and proactive interference. In this study, we therefore examined whether retrieval practice can also reduce list method directed forgetting, a form of intentional forgetting that presupposes interference. In each of two experiments, subjects successively studied two lists of items. After studying each single list, subjects restudied the list items to enhance learning, or they were asked to recall the items. Following restudy or retrieval practice of list 1 items, subjects were cued to either forget the list or remember it for an upcoming final test. Experiment 1 employed a free-recall and Experiment 1 a cued-recall procedure on the final memory test. In both experiments, directed forgetting was present in the restudy condition but was absent in the retrieval-practice condition, indicating that retrieval practice can reduce or even eliminate this form of forgetting. The results are consistent with the view that retrieval practice enhances list segregation processes. Such processes may reduce interference between lists and thus reduce directed forgetting.