Propositions,Numbers, And The Problem Of Arbitrary Identification

Those inclined to believe in the existence of propositions as traditionally conceived might seek to reduce them to some other type of entity. However, parsimonious propositionalists of this type are confronted with a choice of competing candidates – for example, sets of possible worlds, and various neo-Russellian and neo-Fregean constructions. It is argued that this choice is an arbitrary one, and that it closely resembles the type of problematic choice that, as Benacerraf pointed out, bedevils the attempt to reduce numbers to sets – should the number 2 be identified with the set Ø or with the set Ø, Ø? An “argument from arbitrary identification” is formulated with the conclusion that propositions (and perhaps numbers) cannot be reduced away. Various responses to this argument are considered, but ultimately rejected. The paper concludes that the argument is sound: propositions, at least, are sui generis entities.

     

Altering White Racial Identity and Interracial Comfort Through Multicultural Training

The authors examined the impact of multicultural training on the development of White racial identity and interracial comfort. Findings indicated that an integrative multicultural training program resulted in significant increases along 3 dimensions of White racial consciousness and in the levels of interracial comfort. This work extends related efforts to study White racial identity as an important parameter of multicultural training and counseling. In addition, psychometric data and factor structures are provided for the White Racial Consciousness Development Scale (Claney & Parker, 1989) and the Interracial Comfort Index (Claney & Parker, 1989).     

Neuropsychological changes in children with cancer: The treatment of missing data in longitudinal studies

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.     

Speeded recognition of ungrammaticality: Double violations

A model of sentence comprehension postulating that Subject-Verb-Object relations are specified prior to Noun-Adjective relations received support from a study of the speed at which sentences with various kinds of violations could be rejected. Compatible with the sequential model was the finding that Noun-Verb and Adjective-Noun double violations did not result in shorter RTs than Noun-Verb single violations — even though sentences with double violations were judged to be less acceptable.     

Mother rats interact differently with male and female offspring.

Lactating Long-Evans rats were observed to interact differently with male and female pups during the first 18 days postpartum. Differences in the mother's behavior were related to the gender composition of her litter (GHL), to the sex of a single introduced pup, and to the sex of individual pups within her litter. Major differences were the greater time spent in licking the anogenital region of own male pups and the greater stimulation of anogenital licking by male foster pups, an effect that did not interact with GHL or age of pup. The GHL interacted with day of testing to affect nest building and time spent near pups.     

Delayed matching in the pigeon: Effect on performance of sample-specific observing responses and differential delay behavior

Pigeons were trained on a delayed matching-to-sample task with a 0-sec delay and then transferred to a 1-sec delay (Experiment 1) or were trained with mixed 0-sec/1-sec delays and then transferred to longer mixed delays up to 28 sec (Experiment 2). Four groups were distinguished by the nature of the observing response required to each sample color (red and blue). For Group NN pecks were allowed to neither color. For Group PcPc pecks were required to both colors. For Group PcN pecks were required to red but were not allowed to blue. For Group PcPt pecks were required at the center key in the presence of red, but at a key located directly above the center key in the presence of blue. The results of both experiments indicated significant effects of both Pecking vs Not Pecking, and Sample-Specific vs Sample-Independent Responding. At the longer delays individual differences in sample-specific delay behavior were a better predictor of performance than the behavior required in the presence of the sample.     

Asymmetric transfer of prototype information between vision and audition

Specific and nonspecific transfer of pattern class concept information between vision and audition was examined. In Experiment 1, subjects learned visually or auditorily to distinguish between two pattern classes that were either the same as or different from the test classes. All subjects were then tested on the auditory classification of 50 patterns. Specific intramodal and cross-modal transfer was noted; subjects trained visually and auditorily on the test classes were equivalent in performance and more accurate than untrained controls. In Experiment 2, the training of Experiment 1 was repeated, but subjects were tested visually. There was no evidence of auditory-to-visual transfer but some suggestion of nonspecific transfer within the visual modality. The asymmetry of transfer is discussed in terms of the modality into which patterns are most likely translated for the cross-modal tasks and in terms of the quality of prototype formation with visual versus a,ditory patterns.     

Socially mediated fear reduction in rodents: Distraction,communication, or mere presence?

Two studies investigated why the presence of conspecifics reduces open-field fear. In Experiment 1 rats paired with another experimentally naive rat were not less fearful than alone controls. However, rats paired with a partner who had been preexposed to the open field exhibited fewer fear responses than alone controls. Since preexposed companions appeared to initiate more social interactions than nonpreexposed companions, it was argued that the preexposure effect could be the result of preexposed companions distracting actor rats from threatening stimuli. Experiment 2 tested this explanation by pairing socially sated or socially deprived rats with a socially sated or socially deprived companion. In accord with a distraction hypothesis, pairing two socially deprived rats produced the greatest fear reduction effects and also led to more social interaction than pairing socially sated rats. Alternative explanations involving conditioning and communication are discussed.