A social identity theory of leadership

A social identity theory of leadership is described that views leadership as a group process generated by social categorization and prototype-based depersonalization processes associated with social identity. Group identification, as self-categorization, constructs an intragroup prototypicality gradient that invests the most prototypical member with the appearance of having influence; the appearance arises because members cognitively and behaviorally conform to the prototype. The appearance of influence becomes a reality through depersonalized social attraction processes that make followers agree and comply with the leader's ideas and suggestions. Consensual social attraction also imbues the leader with apparent status and creates a status-based structural differentiation within the group into leader(s) and followers, which has characteristics of unequal status intergroup relations. In addition, a fundamental attribution process constructs a charismatic leadership personality for the leader, which further empowers the leader and sharpens the leader-follower status differential. Empirical support for the theory is reviewed and a range of implications discussed, including intergroup dimensions, uncertainty reduction and extremism, power, and pitfalls of prototype-based leadership.

Age changes in personality traits and their heritabilities during the adult years: evidence from Australian Twin Registry samples

Short versions of four Eysenck personality scales had been included in questionnaires given to several adult samples from the Australian Twin Registry, comprising altogether some 5400 pairs. Means and regressions with age are compared for three samples at average ages of 23, 37, and 61 years, and for two samples of retested individuals, one tested twice at average ages of 29 and 37 years, and one tested three times at average ages of 45, 56, and 62 years, For both males and females the trends for Psychoticism (P), Extraversion (E), and Neuroticism (N) were generally downward with age, and for Lie (L), upward. However, in the longitudinal sample between ages 56 and 62 the trends for P, E, and I stopped or reversed, although N continued downward. Heritabilities were reasonably stable across age for P, E, and N, and the effects of shared environments negligible, but L showed some influence of shared environment as well as genes in all but the oldest age group. (C) 2001 Elsevier Science Ltd. All rights reserved.

Comparison between Eysenck's and Gray's models of personality in the prediction of motivational work criteria

Impulsivity based on Gray's [Gray, J. A. (1982) The neuropsychology of anxiety: an enquiry into the function of the septo-hippocampal system. New York: Oxford University Press: (1991). The neurophysiology of temperament. In J. Strelau & A. Angleitner. Explorations in temperament: international perspectives on theory and measurement. London. Plenum Press]. physiological model of personality was hypothesised to be more predictive of goal oriented criteria within the workplace than scales derived From Eysenck's [Eysenck. H.J. (1967). The biological basis of personality. Springfield, IL: Charles C. Thompson.] physiological model of personality. Results confirmed the hypothesis and also showed that Gray's scale of Impulsivity was generally a better predictor than attributional style and interest in money. Results were interpreted as providing support for Gray's Behavioural Activation System which moderates response to reward. (C) 2001 Elsevier Science Ltd. All rights reserved.

A comparison between three and five factor models of Pakistani personality data

The Eysenck Personality Questionnaire-Revised (EPQ-R), the Eysenck Personality Profiler Short Version (EPP-S), and the Big Five Inventory (BFI-V4a) were administered to 135 postgraduate students of business in Pakistan. Whilst Extraversion and Neuroticism scales from the three questionnaires were highly correlated, it was found that Agreeableness was most highly correlated with Psychoticism in the EPQ-R and Conscientiousness was most highly correlated with Psychoticism in the EPP-S. Principal component analyses with varimax rotation were carried out. The analyses generally suggested that the five factor model rather than the three-factor model was more robust and better for interpretation of all the higher order scales of the EPQ-R, EPP-S, and BFI-V4a in the Pakistani data. Results show that the superiority of the five factor solution results from the inclusion of a broader variety of personality scales in the input data, whereas Eysenck's three factor solution seems to be best when a less complete but possibly more important set of variables are input. (C) 2001 Elsevier Science Ltd. All rights reserved.

Correlates of the Eysenck personality profiler

In this two part study, 811 participants completed the Eysenck Personality Profiler (EPP) and the Honey and Mumford Learning Styles Questionnaire (LSQ) and 263 adults completed the EPP and the Myers-Briggs Type Indicator (MBTI). As predicted there were many significant correlations which add to the concurrent validity of the EPP. When the overlap of the EPP with the MBTI and LSQ is compared with the overlap of the NEO-PI with the MBTI and LSQ (derived from Furnham, 1996a,b) it appears that the EPP has greater similarity with the LSQ, but the NEO-PI has greater similarity with the MBTI. (C) 2001 Elsevier Science Ltd. All rights reserved.

Moderating effect of ear preference on personality in the prediction of sales performance

This study examined the relationship between ear preference, personality, and performance ratings on 203 telesales staff. Social desirability scores were a significant predictor of two relatively independent sets of supervisor ratings (actual performance and developmental potential) in interaction with ear preference. It was found that the social desirability scale was a significant positive predictor for staff preferring a right ear headset, but a negative predictor for staff preferring a left ear headset. These results were interpreted in terms of different strategies used to achieve successful sales.

The genetic and environmental relationship between the interpersonal sensitivity measure (IPSM) and the personality dimensions of Eysenck and Cloninger

A shortened version of the Interpersonal Sensitivity Measure (IPSM) developed to predict depression prone personalities was administered in a self-report questionnaire to a community-based sample of 3269 Australian twin pairs aged 18-28 years, along with Eysenck's EPQ and Cloninger's TPQ. The IPSM included four sub-scales: Separation Anxiety (SEP); Interpersonal Sensitivity (INT); Fragile Inner-Self (FIS); and Timidity (TIM). Univariate analysis revealed that individual differences in the IPSM sub-scale scores were best explained by additive genetic and specific environmental effects. Confirming previous research findings, familial aggregation for the EPQ and TPQ personality dimensions was entirely due to additive genetic effects. In the multivariate case, a model comprising additive genetic and specific environmental effects best explained the covariation between the latent factors for male and female twin pairs alike. The EPQ and TPQ dimensions accounted for moderate to large proportions of the genetic variance (40-76%) in the IPSM sub-scales, while most of the non-shared environment variance was unique to the IPSM sub-scales. (C) 2001 Elsevier Science Ltd. All rights reserved.

Irrational schematic beliefs and psychological distress in caregivers of people with traumatic brain injury

Objective: To investigate the relation between irrational schematic beliefs and psychological distress in caregivers of persons with traumatic brain injury (TBI). Design: Cross-sectional mail survey. Participants: One hundred sixteen caregivers of persons with TBI living in the Australian states of Victoria and Queensland who were members of community support groups and brain injury associations. Measures: The Irrational Beliefs Inventory, Brief Symptom Inventory, income satisfaction, degree of personality and behavior change in the TBI individual, and injury severity. Results: Hierarchical regression analyses showed that after controlling for the effects of characteristics of the caregiving situation and the individual with TBI, greater adherence to irrational beliefs was related to higher levels of global psychological distress. Specifically, irrational beliefs related to Worrying were associated with all areas of psychological distress. Conclusion: Results support the cognitive theory proposal that irrational beliefs play an important role in the adaptation to TBI caregiving. Findings suggest the inclusion of cognitive therapy strategies in interventions for caregivers.

Analysis of acousto-ultrasonic characteristics for contact-type transducers coupled to composite laminated plates

The acousto-ultrasonic (AU) input-output characteristics for contact-type transmitting and receiving transducers coupled to composite laminated plates are considered in this paper. Combining a multiple integral transform method, an ordinary discrete layer theory for the laminates and some simplifying assumptions for the electro-mechanical transduction behaviour of the transducers, an analytical solution is developed which can deal with all the wave processes involved in the AU measurement system, i.e, wave generation, wave propagation and wave reception. The spectral response of the normal contact pressure sensed by the receiving transducer due to an arbitrary input pulse excited by the transmitting transducer is obtained. To validate the new analytical-numerical spectral technique in the low-frequency regime, the results are compared with Mindlin plate theory solutions. Based on the analytical results, numerical calculations are carried out to investigate the influence of various external parameters such as frequency content of the input pulse, transmitter/receiver spacing and transducer aperture on the output of the measurement system. The results show that the presented analytical-numerical procedure is an effective tool for understanding the input-output characteristics of the AU technique for laminated plates. (C) 2001 Elsevier Science Ltd. All rights reserved.

Stable expression of noncytopathic Kunjin replicons simulates both ultrastructural and biochemical characteristics observed during replication of Kunjin virus

This report focuses mainly on the characterization of a Vero cell line stably expressing the flavivirus Kunjin (KUN) replicon C20SDrep (C20SDrepVero). We showed by immunofluorescence and cryoimmunoelectron microscopy that unique flavivirus-induced membrane structures, termed convoluted membranes/paracrystalline structures, were induced in the C20SDrepVero cells. These induced cytoplasmic foci were immunolabeled with KUN virus anti-NS3 antibodies and with antibodies to the cellular markers ERGIC53 (for the intermediate compartment) and protein disulfide isomerase (for the rough endoplasmic reticulum). However, in contrast to the large perinuclear inclusions observed by immunofluorescence with anti-double-stranded (ds)RNA antibodies in KUN virus-infected cells, the dsRNA in C20SDrepVero cells was localized to small isolated foci scattered throughout the cytoplasm, which were coincident with small foci dual-labeled with the trans-Golgi specific marker GaIT. importantly persistent expression of the KUN replicons in cells did not produce cytopathic effects, and the morphology of major host organelles (including Golgi, mitochondria, endoplasmic reticulum, and nucleus) was apparently unaffected. The amounts of plus- and minus-sense RNA synthesis in replicon cells were similar to those in KUN virus-infected cells until near the end of the latent period, but subsequently increases of about 10- and fourfold, respectively, occurred in infected cells. Virus-specified protein synthesis in C20SDrepVero cells was also about 10-fold greater than that in infected cells. When several KUN replicon cell lines were compared with respect to membrane induction, the relative efficiencies increased in parallel with increases in viral RNA and protein synthesis, consistent with the increases observed during the virus infectious cycle. Based on these observations, cell lines expressing less-efficient replicons may provide a useful tool to study early events in flavivirus RNA replication, which are difficult to assess in Virus infections. (C) 2001 Academic press.

Predicting coal ash slag flow characteristics (viscosity model for the Al2O3-CaO-'FeO'-SiO2 system)

A model has been developed which enables the viscosities of coal ash slags to be predicted as a function of composition and temperature under reducing conditions. The model describes both completely liquid and heterogeneous, i.e. partly crystallised, slags in the Al2O3-CaO-'FeO'-SiO2 system in equilibrium with metallic iron. The Urbain formalism has been modified to describe the viscosities of the liquid slag phase over the complete range of compositions and a wide range of temperatures. The computer package F * A * C * T was used to predict the proportions of solids and the compositions of the remaining liquid phases. The Roscoe equation has been used to describe the effect of presence of solid suspension (slurry effect) on the viscosity of partly crystallised slag systems. The model provides a good description of the experimental data of fully liquid, and liquid + solids mixtures, over the complete range of compositions and a wide range of temperatures. This model can now be used for viscosity predictions in industrial slag systems. Examples of the application of the new model to coal ash fluxing and blending are given in the paper. (C) 2001 Elsevier Science Ltd. All rights reserved.