Self-reported emotional and behavioral problems in Swedish 14 to 15-year-old adolescents: a study with the self-report version of the Strengths and Difficulties Questionnaire

The psychometric properties of the Swedish self-report version of the Strengths and Difficulties Questionnaire (SDQ-s), and the prevalence of emotional and behavioral problems as measured by the SDQ-s, were studied in 14 to 15-year-old adolescents. The psychometric properties were found to be similar to those found in other language versions, in terms of similar factor structure and acceptable test-retest stability, but low internal consistencies for some of the subscales. There was evidence of good convergent and discriminant validity. The results with regard to gender differences replicated previous findings in other countries, the girls reporting more emotional symptoms and more prosocial behavior, and the boys reporting more conduct problems and tending to report more peer problems. It is concluded that the results are in favor of using the Swedish SDQ-s as a screening instrument for adolescents, despite the low internal consistencies of some of its subscales.     

Sensitivity of muscle force estimates to variations in muscle-tendon properties

The aim of this study was to determine the sensitivity of muscle force estimates to changes in some of the parameters which are commonly used to describe models of muscle-tendon actuation. The sensitivity analysis was performed on three parameters: optimal muscle-fiber length, muscle physiological cross-sectional area (PCSA), and tendon rest length. The muscles selected for the analysis were posterior gluteus medius/minimus, vasti, soleus, and sartorius. Each parameter was perturbed from its nominal value, and an optimization problem was solved to determine the relative influence of each parameter on the calculated values of muscle force. Muscle forces were calculated for a simulated cycle of normal walking. Parameter sensitivity was quantified using two new metrics: an integrated sensitivity ratio, which quantified the effect of changing a single parameter for any muscle on the time history of force developed by that muscle; and a summed cross-sensitivity ratio, which quantified the effect of changing one parameter for any muscle on the time histories of forces developed by all of the other muscles. The results showed that muscle force estimates for walking are most sensitive to changes in tendon rest length and least sensitive to changes in muscle PCSA. For soleus, for example, the integrated sensitivity ratios for tendon rest length were an order of magnitude greater than those for muscle-fiber length and PCSA. For vasti, the integrated sensitivity ratios for tendon rest length were twice as large as those for muscle-fiber length and nearly an order of magnitude greater than those for PCSA. Overall, changes in the tendon rest lengths of vasti and soleus and changes in the fiber length of vasti were most critical to model estimates of muscle force. Our results emphasize the importance of obtaining accurate estimates of tendon rest length and muscle-fiber length, particularly for those actuators that function as prime movers during locomotion (gluteus maximus, gluteus medius/minimus, vasti, soleus, and gastrocnemius).     

Seeing is Believing? Comparing Negative Affect,Realism and Presence in Visual Versus Written Guardianship Scenarios

We compared participant responses on three written guardianship scenarios versus visualized versions of the same scenarios in terms of realism, presence, negative affect elicited by the situation, perceived risk, and the choice to intervene. We find that people who received the visual scenarios report higher presence, but not realism, than those who received the written version. Furthermore, visual scenarios elicited stronger negative affect and resulted in a lower likelihood to intervene. Finally, presence, but not negative affect, mediated the relation between condition and the choice to intervene. Implications of the visual scenario method for future research are discussed.     

The consequence of a limited-capacity short-term memory on repeated visual search

ABSTRACT

When participants search the same letter display repeatedly for different targets we might expect performance to improve on each subsequent search as they memorize characteristics of the display. However, here we find that search performance improved from a first search to a second search but not for a third search of the same display. This is predicted by a simple model that supports search with only a limited capacity short-term memory for items in the display. To support this model we show that a short-term memory recency effect is present in both the second and the third search. The magnitude of these effects is the same in both searches and as a result there is no additional benefit from the second to the third search.     

Response scales as frames of reference: The impact of frequency range on diagnostic judgements

In social and psychological research, respondents are often asked to report the frequency of a behaviour by checking the appropriate alternative from a list of response categories provided to them. Previous research indicated that respondents extract comparison information from the range of the response alternatives, assuming that the average respondent is represented by values in the middle range of the scale, and that the extremes of the scale represent the extremes of the distribution. Extending this line of research, the present studies demonstrate that the users of a respondent's report are also likely to use the range of the response alternatives as a frame of reference in evaluating the implications of the report. Specifically, subjects are found to draw different conclusions about the respondent's personality (Experiment l ), or the severity of his or her medical condition (Experiment 21, from the same absolute frequency report, depending upon the range of the response scale on which the frequency was checked. Moreover, experienced medical doctors were as likely to be influenced by scale range as first-year medical students, suggesting that the phenomenon is of considerable applied importance. Implications for the use of response alternatives in psychological research and diagnostic judgement are discussed.     

Granulocyte activation in humans is modulated by psychological stress and relaxation

Our aim was to study the possible relationship between psychological stress and granulocyte activation primarily in healthy students during an examination period (n = 11) and also in chronically anxious patients (n = 15). We employed cell surface markers: lactoferrin, L-selectin, alphaMbeta2-integrin and CD15s and flow cytometry to detect changes in the activation state of granulocytes, with the start of the stressed state in students at the beginning of an examination period, which was associated with elevated blood plasma cortisol level, and following relaxation hypnosis in both students, during their examination term, and patients. The ratios of all four types of marker-carrier granulocytes increased at the start of the examination period in students; an especially dramatic (ca. 5-fold) enhancement was observed in the proportion of lactoferrin-bearing cells relatively to the pre-examination term value. After hypnosis, the percentage of lactoferrin-exposing granulocytes decreased considerably both in students and in patients, by about half; a similar decrease was observed in the ratio of CD15s-carrier cells in patients. No significant alteration was observed during the study in state or trait anxiety levels, and in total or differential leukocyte counts. Thus, granulocyte activation could be associated with stress, while relaxation may facilitate reducing activation of these cells. In both groups of subjects, granulocyte surface lactoferrin appeared to be a sensitive "stress indicator". This needs further evaluation.     

A longitudinal latent variable analysis of reciprocal relations between depressive symptoms and delinquency during adolescence

In this longitudinal study, reciprocal relations between depressive symptoms and delinquent behavior were examined for a sample of 1,218 male and female adolescents (mean age, 15.51 years at Time 1). Associations were examined within a latent variable approach, controlling for indicator-specific tendencies, students' age and parental education, time-specific 3rd-variable influences, level of prior problem behavior, and measurement error. Findings thus provided relatively unbiased estimates of existing plausible causal relations. Analyses revealed a relatively small unidirectional effect of delinquency on depression for boys (at 1 of 3 time points), and bidirectional effects of comparable size for girls. The circular process for the girls was explained drawing on gender socialization theory and theories of offending behavior. Implications for preventive interventions are also discussed.     

Relationship power and betrayal experience as predictors of reactions to infidelity

Explanations for sexual infidelity have been dominated by an evolutionary psychological theory of jealousy that finds its strongest support in research that employs a forced-choice hypothetical infidelity paradigm wherein participants imagine experiencing infidelity and choose whether sexual or emotional infidelity would be more distressing. Robust gender differences that support evolutionary psychological perspectives are consistently found using this paradigm, but recent work suggests that gender differences may be attenuated among actual infidelity victims. However, no research has used the forced-choice paradigm to compare real and hypothetical infidelity. This study uses this paradigm to compare reactions to imagined dating infidelity to those of infidelity victims. No gender differences are observed in response to the forced-choice question among victims of infidelity. Gender differences among participants who imagined infidelity are partially mediated by level of relationship power. Difficulties with the hypothetical forced-choice paradigm and implications for the evolutionary psychological theory of jealousy are discussed.