The effect of additional variables on factor indeterminacy in models with a single common factor

Determinate solutions for the indeterminate common factor ofp variables satisfying the single common factor model are not unique. Therefore an infinite sequence of additional variables that conform jointly with the originalp variables to the original single common factor model does not determine a unique solution for the indeterminate factor of thep variables (although the solution is unique for the factor of the infinite sequence). Other infinite sequences may be found to determine different solutions for the factor of the originalp variables. The paper discusses a number of theorems about the effects of additional variables on factor indeterminacy in a model with a single common factor and draws conclusions from them for factor theory in general.     

Performance of Dyslexic Children on Cerebellar and Cognitive Tests

In a previous study (A. J. Fawcett, R. I. Nicolson, & P. Dean, 1996), the authors had found strong behavioral evidence for cerebellar deficit in a panel of children with dyslexia. In the present study, the generality of those results was assessed. A battery of clinical tests for cerebellar dysfunction was administered, together with selected cognitive tests, to a further 59 dyslexic and 67 control children. The dyslexic children showed highly significant impairments on the cerebellar tests, with deficits on postural stability and muscle tone comparable in magnitude with their reading and spelling deficits. Furthermore, over 95&percent; of the dyslexic children showed clear evidence of deficit on muscle tone or stability. The findings provide further evidence of the generality of cerebellar impairment in dyslexia. The implications of the cerebellar tests for screening in dyslexia are discussed.     

Why Do Some Owners Allow Their Dogs to Foul the Pavement? The Social Psychology of a Minor Rule Infraction1

This study combines observational, attitudinal, and self‐report measures, and compares a group of irresponsible dog owners who allow their dogs to foul with a control group of responsible owners who clean up after their dogs. The owners are compared on a variety of attitudinal and personal orientation measures. We observed 101 instances of dog fouling in both park and pavement, and 87 respondents subsequently returned questionnaires. The majority (59%) of people observed cleaned up after their dogs. The irresponsible owners were significantly more tolerant of fouling (dog feces were seen as natural waste and biodegradable) and were more likely to agree that the laws were illegitimate and restrictive.     

Remembering specific features of emotional events across time: The role of REM sleep and prefrontal theta oscillations

When an episode of emotional significance is encountered, it often results in the formation of a highly resistant memory representation that is easily retrieved for many succeeding years. Recent research shows that beyond generic consolidation processes, rapid eye movement (REM) sleep importantly contributes to this effect. However, the boundary conditions of consolidation processes during REM sleep, specifically whether these extend to source memory, have not been examined extensively. The current study tested the effects of putative consolidation processes emerging during REM sleep and slow wave sleep (SWS) on item and source memory of negative and neutral images, respectively. Results demonstrate superior emotional relative to neutral item memory retention after both late night REM sleep and early night SWS. Emotional source memory, on the other hand, exhibited an attenuated decline following late night REM sleep, whereas neutral source memory was selectively preserved across early night SWS. This pattern of results suggests a selective preservation of emotional source memory during REM sleep that is functionally dissociable from SWS-dependent reprocessing of neutral source memory. This was further substantiated by a neurophysiological dissociation: Postsleep emotional source memory was selectively correlated with frontal theta lateralization (REM sleep), whereas postsleep neutral item memory was correlated with SWS spindle power. As such, the present results contribute to a more comprehensive characterization of sleep-related consolidation mechanisms underlying emotional and neutral memory retention. Subsidiary analysis of emotional reactivity to previously encoded material revealed an enhancing rather than attenuating effect of late night REM sleep on emotional responses.     

Polysynaptic potentiation at different levels of rat olfactory pathways following learning

This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed.