Efficient Hessian computation using sparse matrix derivatives in RAM notation

This article proposes a new, more efficient method to compute the minus two log likelihood, its gradient, and the Hessian for structural equation models (SEMs) in reticular action model (RAM) notation. The method exploits the beneficial aspect of RAM notation that the matrix derivatives used in RAM are sparse. For an SEM with K variables, P parameters, and P′ entries in the symmetrical or asymmetrical matrix of the RAM notation filled with parameters, the asymptotical run time of the algorithm is O(P?′?K ²?+?P ² K ²?+?K ³). The naive implementation and numerical implementations are both O(P ² K ³), so that for typical applications of SEM, the proposed algorithm is asymptotically K times faster than the best previously known algorithm. A simulation comparison with a numerical algorithm shows that the asymptotical efficiency is transferred to an applied computational advantage that is crucial for the application of maximum likelihood estimation, even in small, but especially in moderate or large, SEMs.     

Continuity of temperament from infancy to middle childhood

Continuity of temperament from 6 months (the IBQ) to 5.5 years (the CBQ) was explored in Finnish children (n = 231) within the theoretical framework deviced by Rothbart. Activity level, smiling and laughter, distress to limitations and fear showed significant differential homotypic and heterotypic continuity, while soothability and duration of orienting showed significant differential heterotypic continuity. On the level of latent superconstructs, infant positive and negative affectivity accounted for 4.6, 22.3, and 6.0% of the variance in childhood extraversion, effortful control and negative affectivity, respectively. Infant and childhood temperament clustered into profile types named “resilient”, “undercontrolled”, and “overcontrolled” mirroring ipsative continuity. These findings give empirical credence to Rothbart's theory by replicating and extending previous findings in significant ways.     

Reliability and factor structure of the Finnish version of the Sport Imagery Questionnaire

The aim of this study was to examine the reliability and factor structure of the Finnish version of the Sport Imagery Questionnaire, a measure which examines cognitive and motivational functions of imagery. The final sample comprised 231 participants drawn from 34 sports and ranging in age from 14 to 49 years (M = 20.9, SD = 5.8). Internal consistency and confirmatory factor analyses were undertaken to evaluate the reliability and factorial validity of the scale. Fit indices and modification data generated from examining the 30-item five-factor model were equivocal, suggesting minor amendment and recategorization of several items rather than major adjustment to the proposed latent factor structure. Cronbach coefficients alpha indicated the scale is reliable. Overall, these results provide positive additional support for the claim that the Sport Imagery Questionnaire has a reproducible factor structure and is a reliable test for measuring imagery use in Finnish athletes.     

Neurocognitive Performance in Children with ADHD and OCD

Attention-deficit/hyperactivity Disorder (ADHD) and obsessive–compulsive disorder (OCD) have both been linked to dysfunction in the cortico-striato-thalamo-cortical circuitry (CSTCC). However, the exact nature of neurocognitive deficits remains to be investigated in both disorders. We applied two neuropsychological tasks that tap into different functions associated with the CSTCC, namely a serial reaction time (SRT) task, developed to assess implicit sequence learning, and a delay aversion (DA) task in order to assess abnormal motivational processes. The performance data of boys with ADHD (n = 20), OCD (n = 20) and healthy controls (n = 25), all aged 10–18 years, were compared. Subjects with ADHD less frequently chose the larger, more delayed reward compared to those with OCD and controls, while subjects with OCD showed impaired implicit learning. In contrast, the ADHD group was unimpaired in their implicit learning behavior and the OCD group was not characterized by a DA style. Within the OCD-group, severity of obsessions was associated with implicit learning deficits and impulsive symptoms with DA in the ADHD-group. This double dissociation highlights the distinct cognitive dysfunctions associated with ADHD and OCD and might possibly point to different neural abnormalities in both disorders.     

Exploring trust of mobile applications based on user behaviors: an empirical study

This paper explores trust of mobile applications based on users' behaviors. It proposes a trust behavior construct through principal component analysis, reliability analysis, and confirmatory factor analysis based on the data collected from a questionnaire survey with more than 1,500 participants. It is indicated that a user's trust behavior is composed of three principal constructs: using behavior, reflection behavior, and correlation behavior. They are further delineated into 12 measurable sub‐constructs and relate to a number of external factors. The data analysis showed that the questionnaire has positive psychometric properties with respect to construct validity and reliability. We also discuss the practical significance and limitations of our work toward usable trust management.     

A Short Measure of the Need for Affect

Summary

Widespread divergencies of opinion exist over the usefulness, the nature, the purpose, and the scientific status of clinical psychological testing. This paper seeks to order these problems in historical and philosophical perspective. Largely different values and orientations have been contributed by traditional American academic psychology, by clinical psychology, and by psychiatry. Academic psychologists advocate a rigorous scientific basis (logical positivism) for testing, which the clinician tends to find overly confining and antagonistic to his humanistic, individual centered, service orientation; while psychiatrists tend to differ greatly among themselves in their understanding of psychological testing and hence exert no uniform influence on the practice. The current trend emphasizes greater sophistication in the academic approach to testing, with advances in empiricism and computer-aided manipulation of data, while the more clinically oriented psychologists seek to strengthen their theoretical position and to demonstrate the effectiveness of their methods through studies of clinical judgment. At the same time basic methodological research to support the “clinical position” is yet too sparse. It is proposed that both academic and clinical approaches have a significant contribution to make to clinical psychological testing. Ultimately the design of psychological tests and the evaluation of their usefulness rests upon what we conceive psychological science to be, and we need to remind ourselves, in this regard, that the conception of science is subject to change.     

Wisselende grense: visuele kuns en alledaagse aktiwiteit

Kontemporêre visuele kuns sluit toenemend aktiwiteite in wat die terrein van alledaagse aktiwiteit betree. Insgelyks penetreer estetiese begrippe wat voorheen tot die kunsdissipline beperk was die sfeer van bestaansroetine en selfs beroepsterreine soos besigheidsbestuur wat voorheen as onversoenbaar met die kunste beskou was. Die gevolg is dat die konvensionele grense tussen kunsaktiwiteit, en enige ander aktiwiteit, ook die skryf van tekste oor die visuele kuns, onder druk verkeer en ernstige vrae oor die wesenlike inhoud van kuns en selfs die behoud van die kategorie ‘kuns’ ontstaan. Met, as vertrekpunt, die uitsprake en kunsaktiwiteite van die Duitse ‘beeldhouer’, Joseph Beuys, word 'n oorsig aangebied van die wisselwerking tussen visuele kunsvorme en ander alledaagse aktiwiteite. Die implikasies van hierdie transgressie van grense vir oproepe om 'n her-mitologisering van kuns en die aansluitende rekonstruksie van die waardestelsels van die gemeenskap word uit 'n aantal perspektiewe belig, en enkele aansluitende filosofiese interpretasies van die funksie en doel van kunsaktiwiteit word gebruik om die begrip 'artistieke deelname' in reliëf te plaas.