Assessing the forms and functions of aggression using self-report: factor structure and invariance of the Peer Conflict Scale in youths

This study examined the structure of a self-report measure of the forms and functions of aggression in 855 adolescents (582 boys, 266 girls) aged 12 to 19 years recruited from high school, detained, and residential settings. The Peer Conflict Scale (PCS) is a 40-item measure that was developed to improve upon existing measures and provide an efficient, reliable, and valid assessment of four dimensions of aggression (i.e., reactive overt, reactive relational, proactive overt, and proactive relational) in youths. Confirmatory factor analyses showed that a 4-factor model represented a satisfactory solution for the data. The factor structure fit well for both boys and girls and across high school, detained, and residential samples. Internal consistency estimates were good for the 4 factors, and they showed expected associations with externalizing variables (i.e., arrest history, callous-unemotional traits, and delinquency). Reactive and proactive subtypes showed unique associations consistent with previous literature. Implications for the use of the PCS to assess aggression and inform intervention decisions in diverse samples of youths are discussed.     

Filling-in models of completion: rejoinder to Kellman, Garrigan, Shipley, and Keane (2007) and Albert (2007)

There has been a growing interest in understanding the computations involved in the processes underlying visual segmentation and interpolation in conditions of occlusion. P. J. Kellman, P. Garrigan, T. F. Shipley, and B. P. Keane and M. K. Albert defended the view that identical contour interpolation mechanisms underlie modal and amodal completion. In the current rejoinder, the author provides further psychophysical evidence against this view and argues that no physiological data support the claim that modal and amodal contours are represented identically at any stage of processing. The author also shows that the illusory glass surfaces that Kellman et al. and Albert upheld as evidence against his arguments about luminance constraints in completion are explained by theoretical principles that he has previously articulated, and variants of these illusions receive no explanation within either of the models Kellman et al. and Albert propose. The author shows that the principles needed to explain these percepts embody fundamental asymmetries in the way that relative depth shapes segmentation and interpolation processes and that models of completion that lack these constraints--such as P. J. Kellman, P. Garrigan, and T. F. Shipley's and M. K. Albert's --cannot account for a host of documented completion phenomena.     

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.     

Friendships and Romantic Relationships of Black and White Adolescents

Prior research on adolescent peer relationships has focused on interpersonal dimensions of friendships but not of romantic relationships, and has rarely examined minority groups. We used a random sample of 122 adolescents to examine race and gender differences in friendships, romantic relationships, and the congruence between closest friendship and romantic relationship on five interpersonal domains: mutual support, self-disclosure, hurtful conflict, fear of betrayal, and interpersonal sensitivity. Significant race by gender differences in the difference between relationship type for both positive and negative dimensions of relationships were found. White girls reported significantly higher levels of self-disclosure in their friendship ties in comparison to romantic relationship, whereas white boys reported nearly equivalent levels. In comparison to white adolescents, Black adolescent girls and boys had similar levels of self-disclosure in their romantic relationships as their same-sex friendships. With regards to negative elements of relationships, girls reported more hurtful conflict in romance than friendship, whereas boys reported an opposite pattern. Results highlight the importance of consideration of race and gender influences on youth interpersonal skills within peer and romantic relationships.     

A latent class factor approach to identifying subtypes of juvenile diversion youths based on psychopathic features

Latent class factor analysis allows for the estimation of a dimensional construct such as psychopathy through factor analysis while also examining the heterogeneity of the sample. We report the results of a latent class factor analysis examining the psychometric structure of a widely used measure of psychopathy, as well as internalizing (i.e. anxiety) and externalizing indices, among diversion program youths involved in an intervention study. The results indicated that four subgroups of adolescents existed in the data: one with high psychopathic features and externalizing problems, but low anxiety; one with moderately high affective and behavioral psychopathic features and externalizing problems, but low anxiety; one with moderately high interpersonal and behavioral psychopathic features, externalizing problems, and anxiety; and one with very low psychopathy scores, anxiety, and externalizing problems. The validity of these subgroups was assessed comparing prior family problems, substance use, and offending measures, and one‐year follow‐up measures of recidivism, detention days, substance use, and program completion. This study offers partial support for the existence of psychopathy subgroups and has implications for future studies of psychopathy typologies. In addition, this study employed a methodology for classification that permits consideration of the dimensional nature of a construct, and as such has implications for a variety of research areas. Copyright © 2009 John Wiley & Sons, Ltd.     

What Do We Know About Neuropsychological Aspects Of Schizophrenia?

Application of a neuropsychological perspective to the study of schizophrenia has established a number of important facts about this disorder. Some of the key findings from the existing literature are that, while neurocognitive impairment is present in most, if not all, persons with schizophrenia, there is both substantial interpatient heterogeneity and remarkable within-patient stability of cognitive function over the long-term course of the illness. Such findings have contributed to the firm establishment of neurobiologic models of schizophrenia, and thereby help to reduce the social stigma that was sometimes associated with purely psychogenic models popular during parts of the 20th century. Neuropsychological studies in recent decades have established the primacy of cognitive functions over psychopathologic symptoms as determinants of functional capacity and independence in everyday functioning. Although the cognitive benefits of both conventional and even second generation antipsychotic medications appear marginal at best, recognition of the primacy of cognitive deficits as determinants of functional disability in schizophrenia has catalyzed recent efforts to develop targeted treatments for the cognitive deficits of this disorder. Despite these accomplishments, however, some issues remain to be resolved. Efforts to firmly establish the specific neurocognitive/neuropathologic systems responsible for schizophrenia remain elusive, as do efforts to definitively demonstrate the specific cognitive deficits underlying specific forms of functional impairment. Further progress may be fostered by recent initiatives to integrate neuropsychological studies with experimental neuroscience, perhaps leading to measures of deficits in cognitive processes more clearly associated with specific, identifiable brain systems.     

Preattentive texture segmentation: The role of line terminations,size, and filter wavelength

The texel pair represents a dilemma in texture discrimination because, despite having the same component orientations, discrimination is still possible (Julesz, 1981), showing a performance asymmetry. Other possible element properties that could influence this task are line terminations, closure, and the size of these elements. We found that line terminators are critical for the task; however, results from double-task experiments indicated that terminator-based discrimination requires the use of attention. When attention is not available for the task, “size” of the elements (with the considered slightly larger) seems to be critical for this discrimination and for the asymmetric performance. To generalize the concept of “size” to textures in general, further experiments were performed with textures of different-sized elements. Results showed, as past literature has indicated, that there is a performance asymmetry, with the larger of the elements being more visible when in the foreground. This asymmetry was additionally shown to reverse itself (i.e., the smaller element became the more visible) as the scale of the elements increased (while interelement distance remained fixed). A filter analysis was developed in order to measure the apparent size of these elements within textures (texsize), defined as the response weighted average of the filter wavelength, $\bar \lambda $ , for a group of elements. The calculation of $\bar \lambda $ was attained by introducing a nonlinearity after the second stage of filtering (or spatial averaging of filter responses). This analysis showed high correlation between the texture with the larger $\bar \lambda $ and the more visible texture. On the basis of this correlation, a wavelength-dependent noise is proposed, having more internal noise for low-spatial-frequency filters and less for high-spatial-frequency filters.