A Truthmaker Indispensability Argument

Recently, nominalists have made a case against the Quine–Putnam indispensability argument for mathematical Platonism by taking issue with Quine’s criterion of ontological commitment. In this paper I propose and defend an indispensability argument founded on an alternative criterion of ontological commitment: that advocated by David Armstrong. By defending such an argument I place the burden back onto the nominalist to defend her favourite criterion of ontological commitment and, furthermore, show that criterion cannot be used to formulate a plausible form of the indispensability argument.     

Delis-Kaplan Executive Function System

The purpose of the current study was to examine the performance of children with and without ADHD in time reproduction tasks involving varying durations and modalities. Twenty children with ADHD and 20 healthy controls completed time reproduction tasks in three modalities (auditory, visual, and a unique combined auditory/visual condition) and six durations (1 second, 4 seconds, 12 seconds, 24 seconds, 48 seconds, and 60 seconds). Consistent with our predictions, we found main effects of group (participants with ADHD were significantly less accurate than those without ADHD), duration (accuracy decreased as temporal duration increased), and modality (responses in the combined condition were more accurate than those in the auditory condition, which in turn were more accurate than those in the visual condition). Furthermore, predicted interactions between group and duration (the discrepancy in performance between the two groups grew as temporal duration increased), and group and modality (the modality effect was of greater for participants with ADHD) were supported. A marginal, nonsignificant interaction between group, modality, and duration was also found. These findings are discussed in relation to current theory on the nature of cognitive deficits evident in individuals with ADHD, and methodological limitations are noted.     

Test Review: Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV)

Objective: Evaluate neuropsychological functioning in children with non-syndromic cleft of the lip and/or palate (NSCL/P) through profile variance within type of cleft and comparisons to controls.

Methods: Children ages 7 to 17 years participated; 66 had a diagnosis of NSCL/P and 87 were healthy controls. Neuropsychological tests of language, visual-perceptual, executive functioning, and memory skills were administered. Between- and within-group differences were assessed.

Results: Within cleft types, children with NSCLP had an even profile with equal Verbal and Performance IQ (VIQ and PIQ, respectively). Children with non-syndromic cleft palate only (NSCP) had significantly lower VIQ than PIQ, while children with non-syndromic cleft lip only (NSCL) showed a nonsignificant trend for higher VIQ than PIQ. Overall, subjects with NSCL/P performed lower on measures of expressive language and verbal memory than controls.

Conclusions: While deficits in verbal and memory skills for children with NSCL/P remain apparent, there is still uncertainty around the possible influence of cleft type on the pattern of deficits.     

Developmental normative data for the Baron-Hopkins Board test of spatial location memory

Developmentally appropriate domain-specific tests with strong psychometric properties for preschoolers are lacking and infrequently developed. Baron’s modification of the Hopkins Board test (B-HB) to assess spatial location learning and recall in 3- and 6-year-old children has shown promise in the study of young children born prematurely. Current study data were analyzed on 172 typically developing children at age 3 years and 193 at age 6 years, born at term (≥ 37 weeks; ≥ 2500 grams). Statistically significant gender differences were found and data stratification of T-scores and percentile ranks are provided for each of the eight B-HB measures. The B-HB’s strong interrater reliability (99.5%), low-to-moderate test-retest reliability across the 3-year age span, Pearson correlations showing criterion validity, and differential functioning from other selective attention and visuospatial/visuoperceptual tests provide initial normative data for this novel measure of spatial location memory in young children.     

Representing ‘Us’ and ‘Them’: Building Blocks of Intergroup Cognition

Three experiments explored whether group membership affects the acquisition of richer information about social groups. Employing a minimal-groups paradigm, 6- to 8-year-olds were randomly assigned to 1 of 2 novel social groups. Experiment 1 demonstrated that immediately following random assignment to a novel group, children were more likely to generalize negative behaviors to outgroup members and positive behaviors to ingroup members and to report a preference for ingroup members. Experiments 2 and 3 showed that this initial ingroup-favoring bias interacts with subsequent learning, thereby attenuating the effect of negative information about the ingroup and enhancing the effect of negative information about the outgroup. These effects were more powerful with respect to preferences than induction: After hearing that some ingroup members behaved badly, children predicted that ingroup members would behave more negatively than outgroup members, but they did not express preferences for the outgroup over the ingroup. Together these data shed light on the construction of social category knowledge as well as the processes underlying the absence of own-group positivity among children from lower-status social groups.     

Misperceptions in intergroup conflict. Disagreeing about what we disagree about

Two studies examined misperceptions of disagreement in partisan social conflicts, namely, in the debates over abortion (Study 1) and politics (Study 2). We observed that partisans tend to exaggerate differences of opinion with their adversaries. Further, we found that perceptions of disagreement were more pronounced for values that were central to the perceiver's own ideology than for values that were central to the ideology of the perceiver's adversaries. To the extent that partisans assumed disagreement concerning personally important values, they were also inaccurate in perceiving their adversaries' actual opinions. Discussion focuses on the cognitive mechanisms underlying misperceptions of disagreement and strategies for reducing intergroup conflict.     

Preratio pausing: effects of an alternative reinforcer on fixed- and variable-ratio responding

Seven rats responding under fixed-ratio or variable-ratio schedules of food reinforcement had continuous access to a drinking tube inserted into the operant chamber. Under different conditions they could drink either tap water or one of two saccharin solutions. In a baseline condition, the drinking bottle was empty. Preratio pausing was observed with both schedules, more so with the fixed-ratio than the variable-ratio schedule, and increasing the concentration of the saccharin solution increased the duration of pausing. Comparisons with baseline performances revealed that the additional pausing was largely, but not entirely, spent drinking. The results support the view that pausing under ratio schedules is a consequence of competition between the scheduled reinforcer and alternative reinforcers that also are available within the experimental environment.