Color-function categories that prime infants to use color information in an object individuation task

There is evidence for developmental hierarchies in the type of information to which infants attend when reasoning about objects. Investigators have questioned the origin of these hierarchies and how infants come to identify new sources of information when reasoning about objects. The goal of the present experiments was to shed light on this debate by identifying conditions under which infants’ sensitivity to color information, which is slow to emerge, could be enhanced in an object individuation task. The outcome of Experiment 1 confirmed and extended previous reports that 9.5-month-olds can be primed, through exposure to events in which the color of an object predicts its function, to attend to color differences in a subsequent individuation task. The outcomes of Experiments 2-4 revealed age-related changes in the nature of the representations that support color priming. This is exemplified by three main findings. First, the representations that are formed during the color-function events are relatively specific. That is, infants are primed to use the color difference seen in the color-function events to individuate objects in the test events, but not other color differences. Second, 9.5-month-olds can be led to form more abstract event representations, and then generalize to other colors in the test events if they are shown multiple pairs of colors in the color-function events. Third, slightly younger 9-month-olds also can be led to form more inclusive categories with multiple color pairs, but only when they are allowed to directly compare the exemplars in each color pair during the present events. These results shed light on the development of categorization abilities, cognitive mechanisms that support color-function priming, and the kinds of experiences that can increase infants’ sensitivity to color information.     

Factor Analysis of Scales Composed of Binary Items: Illustration with the Maudsley Obsessional Compulsive Inventory

It is well known that traditional factor analytic methods are designed for use with continuous data, and suboptimal for items with 2 response options (i.e., binary items). Nevertheless, traditional methods have been employed in all previous assessment of the dimensionality of the Maudsley Obsessional Compulsive Inventory (MOCI), a true/false measure of obsessive–compulsive symptoms ( R. J. Hodgson &; S. Rachman, 1977). The aim of this paper is to illustrate 2 techniques that are more suitable for factor-analyzing binary items than traditional methods, through application to the MOCI (n = 1,080). Computer files for use with the TESTFACT (D. Wilson, R. L. Wood, &; R. Gibbons, 1991 ) and Mplus (Muthén &; Muthén, 1998) computer programs are provided. Results from an inappropriately applied principal axis factor analysis are presented for comparison, and factor structures, loadings, and interfactor correlations are compared across methods.     

Cognitive Neuropsychology of HIV-Associated Neurocognitive Disorders

Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies. The research described was supported by MH73419 and MH62512 from the National Institutes of Health. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, nor the United States Government.     

Token-economy programmes with chronic psychotic patients: The importance of direct measurement and objective evaluation for long-term maintenance

Direct-observational data collected from 6 example patients over 5 yr on a token-economy ward are presented. Comparison of performance in baseline, contingent-token and non-contingent-token conditions revealed considerable variability within and between both patients and self-care behaviours. For 3 patients the Token-Economy Programme appeared to have a ‘therapeutic’ effect, producing behaviour change that was sustained after the termination of a contingent token regime. For the others, rates of behaviour change were exceptionally slow and the token economy functioned as an essential prosthetic environment. It is suggested that the longevity of the system was related to the conceptional framework and methodology employed. An example of behaviour becoming ‘token bound’ is included.     

Age-related changes in processing auditory stimuli during visual attention: evidence for deficits in inhibitory control and sensory memory.

Age-related declines in attention and cognition have been associated with a difficulty in inhibiting the processing of task-irrelevant information (i.e., the inhibitory deficit hypothesis). However, evidence supporting the inhibitory deficit hypothesis remains equivocal, in part because of complexities in examining the processing of irrelevant stimuli using purely behavioral techniques. The effects of age on the processing of task-irrelevant stimuli were examined using scalp-recorded event-related brain potentials. Participants performed a visual discrimination task while standard and deviant auditory stimuli were presented in the background. Deviant auditory stimuli generated a mismatch negativity (MMN) wave that decreased with age, in part because of an age-related enhancement in sensory-evoked responses. The age-related changes in processing task-irrelevant auditory stimuli are consistent with the inhibitory deficit hypothesis and suggest that impaired inhibitory control of sensory input may play a role in the age-related declines in performance during selective attention tasks.     

Concurrent performances: reinforcement by different doses of intravenous cocaine in rhesus monkeys

Different doses of intravenous cocaine reinforced the lever pressing of rhesus monkeys under two-lever concurrent or concurrent-chain schedules. Under the concurrent procedure, responding produced drug reinforcers arranged according to independent variable-interval 1-min schedules. Under the concurrent-chain procedure, responding in the variable-interval link led to one of two mutually exclusive, equal-valued, fixed-ratio links; completion of the ratio produced a drug reinforcer. Under both procedures, responding on one lever produced a constant dose of 0.05 or 0.1 mg/kg/injection, while on the other lever, dose was systematically varied within a range of 0.013 to 0.8 mg/kg/injection. Preference, indicated by relative response frequency on the variable-dose lever during the variable-interval link, was always for the larger of the doses. Relative response frequencies on the variable-dose lever roughly matched relative drug intake (mg/kg of drug obtained on variable lever divided by mg/kg of drug obtained on both levers). For many dose comparisons, responding occurred and reinforcers were obtained almost exclusively on the preferred lever. Overall variable-interval rates generally were lower than with other reinforcers, and these low rates, under the experimental conditions, may have occasioned the exclusive preferences.     

Repression-sensitization and nonverbal expressiveness

Investigated the relationship of status on Byrne's repression-sensitization dimension to novel measures of nonverbal' expressiveness under stress and nonstress conditions, where subjects' perceptions of the purpose of the dependent measures were varied. Forty subjects were divided into sensitizer and repressor groups on the basis of Repression-Sensitization (R-S) scores. Subjects viewed either an anxiety-producing industrial accident film or a control film. Subjects were then told that the purpose of subsequent testing was either the assessment of creativity or of personality, as measured by a new projective test. The 2 X 2 X 2 factorial design enabled the investigation of predictions based on ego-defensive interpretations of repression-sensitization and Lefcourt's "attitude towards emotionality" view. Although the study failed to provide strong support for either interpretation in full, the data were viewed as reconcilable with Lefcourt's theory where repressors, but not sensitizers, are-concerned.