Behavioral contrast as a function of the temporal location of reinforcement

Pigeons were trained on a multiple variable-interval variable-interval schedule of reinforcement. One component was then changed to a variation of a fixed-interval schedule in which the same rate of reinforcement was obtained as previously but the location of the reinforcer was fixed within the component. The effects of different temporal locations were compared. An increase in response rate for the unchanged variable-interval component (behavioral contrast) occurred when the reinforcer was located in the middle or at the end of the FI component, but response suppression occurred when it was located at the beginning of the component. The pattern of results cannot be explained by any previous theories of contrast. The overall response rates, and the pattern of local rates within the components, were consistent with the hypothesis that the major determinant of the contrast effect was the transition to a lower reinforcement rate following the unchanged component.     

Life before and after quitting smoking: an electronic diary study

This article describes a multidimensional, multivariate, and multilevel approach to the assessment of nicotine withdrawal. In this prospective study, 70 adult smokers assigned to an active or placebo nicotine patch condition completed multiple daily assessments using an electronic diary. Average and individual growth curves were estimated for affective and nonaffective withdrawal symptoms. All symptoms but hunger increased significantly on the quit day and remained elevated for three weeks. Variability in symptom experiences across individuals increased from pre- to post-quit. Relations between symptom reports (e.g., negative affect or craving) and episodic events (e.g., stressful events or seeing someone smoke) changed from pre-quit to post-quit. Pre-quit increases in negative affect and quit-day increases in craving were inversely related to abstinence three months after the quit day, suggesting that anticipatory and immediate reactions to quitting influence success.     

Neuropsychologic functioning in children with autism: further evidence for disordered complex information-processing.

A wide range of abilities was assessed in 56 high-functioning children with autism and 56 age- and IQ-matched controls. Stepwise discriminant analyses produced good group discrimination for sensory-perceptual, motor, complex language, and complex memory domains but lower agreement for the reasoning domain than previously obtained for adults. Group discrimination did not occur for attention, simple language, simple memory, and visuospatial domains. Findings provide additional support for a complex information-processing model for autism, previously based on adult data, demonstrating a pattern across domains of selective impairments on measures with high demands for integration of information and sparing when demands were low. Children as compared to adults with autism exhibited more prominent sensory-perceptual symptoms and less pronounced reasoning deficits reflecting brain maturation.     

Ontogeny of the adrenal response to (+)-methamphetamine in neonatal rats: the effect of prior drug exposure

We examined the ontogeny of the corticosterone response to (+)-methamphetamine in neonatal rats. In experiment-1, animals were injected with 10 mg/kg of (+)-methamphetamine or saline and plasma corticosterone levels were examined in separate groups 30 or 105 min later on postnatal day (P) 1, 3, 5, 7, 9, 11, 13, 15, 17, or 19. The adrenal response to methamphetamine was best described by a U-shaped function with the nadir of corticosterone release occurring between P7 and P13. Experiment-2 was similar except that the effect of four consecutive days of exposure to (+)-methamphetamine (four times daily at 2 h intervals with 10 mg/kg) was assessed with a single final dose early on the fifth day (i.e. P1-5, 3-7, 5-9, 7-11, 9-13, 11-15, 13-17, 15-19). The 30 min corticosterone response after multiple methamphetamine doses was augmented compared to single exposures, with the exception of the two earliest dosing intervals ending on P5 and P7, where the responses were lower. In addition, at 105 min, the levels of corticosterone were attenuated relative to a single drug administration. With the exception of animals receiving methamphetamine from P15 to P19, thymus weights were unaffected. The data demonstrate that (+)-methamphetamine is a robust activator of corticosterone release in developing animals and this release is extensively modified by age and previous drug exposure.     

Progress in the Molecular-Genetic Study of Intelligence

ABSTRACT— The past decade has seen a major shift in the genetic study of human intelligence; where classic studies aimed to quantify the heritability of intelligence, current studies aim to dissect this heritability into its molecular-genetic components. Five whole-genome linkage scans have been published in the past year, converging on several chromosomal (or genomic) regions important to intelligence. A handful of candidate genes, some of which lie in these genomic regions, have shown significant association to intelligence and the associations have been replicated in independent samples. Finding genes brings us closer to an understanding of the neurophysiological basis of human cognition. Furthermore, when genes are no longer latent factors in our models but can actually be measured, it becomes feasible to identify those environmental factors that interact and correlate with genetic makeup. This will supplant the long nature–nurture debate with actual understanding.     

Moore’s Paradoxes and Conscious Belief*

For Moore, it is a paradox that although I would be absurd in asserting that (it is raining but I don’t believe it is) or that (it is raining but I believe it isn’t), such assertions might be true. But I would be also absurd in judging that the contents of such assertions are true. I argue for the strategy of explaining the absurdity of Moorean assertion in terms of conscious Moorean belief. Only in this way may the pathology of Moorean absurdity be adequately explained in terms of self-contradiction. David Rosenthal disagrees with this strategy. Ironically, his higher-order thought account has the resources to fulfil it. Indeed once modified and supplemented, it compares favourably with Brentano’s rival account of conscious belief. *This paper was written with the support of a grant from the SMU-Wharton Research center.     

Relations of Parenting and Negative Life Events to Cognitive Diatheses for Depression in Children

In a sample of 299 children (grades 2, 4, and 6), we examined parenting and negative life events as predictors of depressive cognitions, specifically low self-perceived competence, depressive cognitive schemas, and depressogenic attributional style. We also examined developmental trends in these relations. Children completed measures of parenting, negative life events, and depressive cognitions. Parents also completed measures of parenting and negative life events. Consistent with our hypotheses, negative parenting and negative life events corresponded with higher levels of depressive cognitions, whereas positive parenting corresponded with lower levels of depressive cognitions. The relations between negative parenting and negative automatic thoughts were stronger for older children. Theoretical and practical implications are discussed.     

Personality and mood: State-trait relationships

The scores of 33 subjects of the neuroticism scale of the Eysenck Personality Questionnaire correlated more highly with mood levels averaged over the 12 occasions studied than, on average, with mood scores on single occasions, and more highly with mood described in global terms than with scores on each of the original 18 mood scales. Subjects with high neuroticism scores had poorer mood on average and showed greater variation in mood pattern from one occasion to another than did more stable subjects. It is suggested that forms of relatively poor mood may be more varied than forms of good mood, and that, although neuroticism makes a poor mood more likely, the precise composition of this mood on any occasion may be determined by the combination of situation characteristics and person variables. Psychoticism scores correlated significantly, though weakly, with the average scores for some mood scales independently of neuroticism.