Stiffness as a control variable in motor performance

In the experiments described in this article we investigated the control of stiffness of the effector system in relation to parameters of the movement. If the velocity of a movement is chosen, it appears that at the same time the stiffness of the effector system is set to a preferred value. By changing the instruction given to the subject it is possible to change the relationship between velocity and stiffness without changing the kinematic parameters of the movement.Finally, the changes of stiffness and velocity in a learning process are studied. In conformity with what might be expected on intuitive grounds, it is found that velocity increases spontaneously during learning while stiffness decreases. The results are discussed in connection with the generation of motor programmes.     

Hardy personality as moderator variable of burnout syndrome in firefighters

In last years, theorists and researchers have pointed to the relevance of personal factors in resilience and vulnerability on burnout. The purpose of this study was to examine the role of hardy personality as moderator of the relationship between job stressors and burnout. A total of 405 firefighters of the Community of Madrid participated in the study. The results of the hierarchical multiple regression analysis showed that the challenge component of hardy personality buffer the influence of job stressors on the occurrence of burnout. Results support the hypothesis that hardy personality may have moderator effects on burnout. Furthermore, commitment appeared as a mediator of the relationships between burnout and its associated symptomatology. Finally, discussion emphasized the need to focus on the interaction between personal and contextual factors in order to make advances in understanding the burnout process.     

Delinquent personality types and the situational contexts of their crimes

Eysenck's theory is quoted as an example of a dispositional crime theory. This is in direct contrast to situational crime theory which rejects the notion of the influence of fixed psychological characteristics and stresses the importance of immediate situational stimuli in the explanation of crime. Recent studies of Eysenck's theory have argued the heterogeneity of personality types in the delinquent population, and following Eysenck's suggestion the offences committed by different personality types have been investigated. In the absence of positive results the present research seeks to progress beyond the offence label to compare different personality types on a range of offence-related situational features. This is viewed as an attempt to accommodate situational considerations in what remains essentially a dispositional approach. Similar deliquent personality types to recent studies merge, but they could not be distinguished across the situational-context factors of their offences. However, an alternative methodology to investigate this question is proposed.     

Fear of success as a situational phenomenon

This study was designed to determine whether different arousing situations will generate different responses in fear-of-success (FOS) and performance behavior. Female subjects were given instructions stating that the tasks they were going to complete would later be evaluated by a panel of males, females, or persons in order to determine whether the panel would select them as a potential friend, co-worker, or acquaintance. Results indicated that no significant differences in FOS were due to the different situations. However, there was evidence to conclude that level of performance behavior depends on the situation in which it is measured. Possible explanations for the failure to find FOS situational are discussed, as well as the inability to explain the significant interaction in performance behavior.     

Locus of control and socialization

On the basis of classical association theory, it was predicted that an external locus of control would characterize undersocialization. This hypothesis was tested on a random sample of secondary school children, using a battery of self-report “socialization-delinquent personality” measures to assess degree of socialization. Factorial validity for the use of these measures was obtained from a factor analysis which uncovered a general factor of socialization, while evidence for convergent validity was derived from the relationship between these scales and teacher ratings of refractory behavior. Scores from the Child Nowicki-Strickland Internal-External Scale were found to predict undersocialization in the expected direction. Several possible interpretations of this relationship were suggested and a biosocial explanation was advanced to account for the possible simultaneous development of both externality and undersocialization.     

Locus of control and delinquency

A sample of delinquent and nondelinquent male adolescents was assessed with respect to locus of control and intellectual achievement responsibility. Data were also gathered concerning age, family size, birth order, socioeconomic status, race, and school grade. Results were subjected to a multivariate analysis and showed support for a multidimensional model of locus of control. There was no difference in expectancy of control for negative academic events between delinquents and nondelinquents. In general, birth order and delinquency were the two most important determinants of locus of control. Results are discussed in terms of previous literature on locus of control with particular consideration paid to expectations of control.     

Locus of control as a contributing factor in the relation between self-perception and adolescent aggression

Researchers continue to debate the role of self-esteem in aggression, but research has shown a consistent association between narcissism and aggression in adults and adolescents [e.g., Barry et al., 2007; Bushman and Baumeister, 1998; Stucke, 2007]. The primary aim of the current study was to examine whether locus of control (LOC) moderated the relation between self-perception variables (i.e., self-esteem and narcissism) and aggression in adolescents. Participants were 174 youth (145 males, 26 females) between the ages of 16 and 19 who were enrolled in a voluntary residential program for youth who have dropped out of school. The results showed that LOC moderated the association between self-esteem and aggression such that low self-esteem was associated with higher levels of aggression for individuals with an external LOC. Contrary to expectations, LOC failed to moderate the narcissism-aggression relation. The implications of this study for understanding how self-perception is related to adolescent aggression are discussed.     

Tau as a potential control variable for visually guided braking

D. N. Lee (1976) described a braking strategy based on optical expansion in which the driver brakes so that the target's time-to-contact declines around a constant slope in the range -0.5 < or = tau < 0. The present results from a series of braking simulations confirm and extend earlier reports (E. H. Yilmaz & W. H. Warren, 1995) that performance is broadly compatible with the tau hypothesis. However, performance was not enhanced in situations that favored the estimation of tau, and unlike in earlier reports, performance deteriorated in the absence of a ground plane that provided information about speed and target distance. This finding suggests that the tau hypothesis does not provide a complete account of braking control.