Johannes Schult

Effective prevention of stress-induced sweating and axillary malodour formation in teenagers.

Emotional sweating and malodour production represent a relevant challenge to today’s antiperspirant (AP) and deodorant products as stress in everyday life increases continuously. The aim of this study was to investigate stress‐induced sweating in teenagers who are known to experience various stressful situations, e.g. exams at school or job interviews. To induce emotional sweating in 20 female and 20 male adolescents (16–18 years of age), we applied the Trier Social Stress Test (TSST), considered today to be the most reliable and standardized stress protocol. In this study, we demonstrate that the TSST induces high amounts of sweat and strong axillary malodour in the tested age group. Notably, male teenagers showed significantly higher stress‐induced odour scores than female subjects, although no gender differences were detected concerning other physiological stress markers. Testing of a novel deodorant/AP product developed to specifically address the needs of adolescent consumers revealed excellent deodorant and AP efficacy under the challenging conditions of the TSST.

Effects of powdered fertilized eggs on the stress response

BACKGROUND & AIMS Effects of nutritional supplements on psychological wellbeing receive increasing attention. This double-blind placebo-controlled study investigated effects of a four week intake of powder of fertilized eggs (Young Tissue Extract; YTE) in a laboratory protocol (Trier Social Stress Test; TSST). METHODS Aside the laboratory stress test, we examined differential effects on subjects with high and low levels of chronic stress. Thus, subjects were further divided into two subgroups with scores for chronic stress scores below and above average, respectively. RESULTS Compared to placebo, a four week intake of YTE did not result in superior effects on general wellbeing. However, beneficial effects of YTE were observed in subjects with enhanced levels of chronic stress. When compared to placebo these subjects showed an improvement of both the psychological and endocrine stress response. CONCLUSIONS Group differences suggest that YTE selectively improves adaptation to acute stress by normalizing the endocrine and the subjective stress response. Subjects with less chronic stress also reported less subjective stress but did not show beneficial effects on the endocrine stress response.

Sex‐Specific Differential Prediction of Academic Achievement by German Ability Tests

Tests of cognitive ability play a major role in the selection of students. Still, data regarding the fairness of standardized tests in Germany is scarce. We use three samples (N = 2,616; 58% women) from German universities to investigate the sex‐specific differential prediction of college performance based on intelligence tests. The predictive bias we find is small and in line with US‐American research. The direction of the effect depends on the cognitive ability domain investigated: Numeric test scores are prone to disadvantage women whereas verbal test scores are more likely to discriminate against men. Including high school grade point average in the prediction model can help to offset differential prediction that underestimates womens academic achievement.

Reliability and validity of PIRLS and TIMSS: does the response format matter?

This research was prepared with the support of the German funds “Bund-Lander-Programm fur bessere Studienbedingungen und mehr Qualitat in der Lehre (‘Qualitatspakt Lehre’)” [the joint program of the Federal and States Government for better study conditions and the quality of teaching in higher education (“the Teaching Quality Pact”)] at Saarland University (funding code: 01PL11012). The authors developed the topic and the content of this manuscript independently from this funding. We thank the Institute for School Development Research (IFS) at Technical University Dortmund / the Max Planck Institute for Human Development (MPIB) Berlin / the Standing Conference of the Ministers of Education and Cultural Affairs (KMK) as well as the Research Data Centre (FDZ) at the Institute for Educational Quality Improvement (IQB) for providing the raw data.

Assessing Personality With Multi-Descriptor Items

The need for efficient personality inventories has led to the wide use of short instruments. The corresponding items often contain multiple, potentially conflicting descriptors within one item. In Study 1 (N = 198 university students), the reliability and validity of the TIPI (Ten-Item Personality Inventory) was compared with the reliability and validity of a modified TIPI based on items that rephrased each two-descriptor item into two single-descriptor items. In Study 2 (N = 268 university students), we administered the BFI-10 (Big Five Inventory short version) and a similarly modified version of the BFI-10 without two-descriptor items. In both studies, reliability and construct validity values occasionally improved for separated multi-descriptor items. The inventories with multi-descriptor items showed shortcomings in some factors of the TIPI and the BFI-10. However, the other scales worked comparably well in the original and modified inventories. The limitations of short personality inventories with multi-descriptor items are discussed.

Reliability and Validity of PIRLS and TIMSS

Academic achievements are often assessed in written exams and tests using selection-type (e.g., multiple-choice, MC) and supply-type (e.g., constructed-response, CR) item response formats. The present article examines how MC items and CR items differ with regard to reliability and criterion validity in two educational large-scale assessments with 4th-graders. The reading items of PIRLS 2006 were compiled into MC scales, CR scales, and mixed scales. Scale reliabilities were estimated according to item response theory (international PIRLS sample; n = 119,413). MC showed smaller standard errors than CR around the reading proficiency mean, whereas CR was more reliable for low and high proficiency levels. In the German sample (n = 7,581), there was no format-specific differential validity (criterion: German grades, r ≈ .5; &Dgr;r = 0.01). The mathematics items of TIMSS 2007 (n = 160,922) showed similar reliability patterns. MC validity was slightly larger than CR validity (criterion: mathematics grades; n = 5,111; r ≈ .5, &Dgr;r = −0.02). Effects of format-specific test extensions were very small in both studies. It seems that in PIRLS and TIMSS, reliability and validity do not depend substantially on response formats. Consequently, other response format characteristics (like the cost of development, administration, and scoring) should be considered when choosing between MC and CR.