The relative trustworthiness of inferential tests of the indirect effect in statistical mediation analysis: does method really matter?

A content analysis of 2 years of Psychological Science articles reveals inconsistencies in how researchers make inferences about indirect effects when conducting a statistical mediation analysis. In this study, we examined the frequency with which popularly used tests disagree, whether the method an investigator uses makes a difference in the conclusion he or she will reach, and whether there is a most trustworthy test that can be recommended to balance practical and performance considerations. We found that tests agree much more frequently than they disagree, but disagreements are more common when an indirect effect exists than when it does not. We recommend the bias-corrected bootstrap confidence interval as the most trustworthy test if power is of utmost concern, although it can be slightly liberal in some circumstances. Investigators concerned about Type I errors should choose the Monte Carlo confidence interval or the distribution-of-the-product approach, which rarely disagree. The percentile bootstrap confidence interval is a good compromise test.

Mutual friends' social support and self-disclosure in face-to-face and instant messenger communication.

In the present study, we investigated long-term effects of self-disclosure on social support in face-to-face and instant messenger (IM) communication between mutual friends. Using a representative sample of 583 German IM users, we explored whether self-disclosure and positive experiences with regard to social support would dynamically interact in the form of a reinforcing spiral across three measurement occasions. If mutual friends self-disclose today, will they receive more social support 6 months later? In turn, will this affect their willingness to self-disclose another 6 months later? We further analyzed spill-over effects from face-to-face to IM communication and vice versa. We found that self-disclosure predicted social support and vice versa in IM communication, but not in face-to-face communication. In light of these results, the impact of IM communication on how individuals maneuver friendships through the interplay between self-disclosure and social support are discussed.

Longitudinal patterns of problematic computer game use among adolescents and adults--a 2-year panel study.

AIMS: To investigate the longitudinal patterns (stability and change) of problematic computer game use and its interdependencies with psychosocial wellbeing in different age groups. DESIGN: Three-wave, annual panel study using computer-assisted telephone surveys. SETTING: Germany. PARTICIPANTS: A total of 112 adolescents aged between 14 and 18 years, 363 younger adults between 19-39 years and 427 adults aged 40 years and older (overall n = 902). MEASUREMENTS: Problematic game use was measured with the Gaming Addiction Short Scale (GAS), which covers seven criteria including salience, withdrawal and conflict. Additionally, gaming behaviour and psychosocial wellbeing (social capital and support, life satisfaction and success) were measured in all three panel waves. FINDINGS: The generally low GAS scores were very stable in yearly intervals [average autocorrelation across waves and age groups: r = 0.74, confidence interval (CI) = 0.71, 0.77]. Only nine respondents (1%, CI = 0.5, 1.9) consistently exhibited symptoms of problematic game use across all waves, while no respondent could be classified consistently as being addicted according to the GAS criteria. Changes in problematic gaming were not related consistently to changes in psychosocial wellbeing, although some cross-lagged effects were statistically significant in younger and older adult groups. CONCLUSIONS: Within a 2-year time-frame, problematic use of computer games appears to be a less stable behaviour than reported previously and not related systematically to negative changes in the gamers' lives.

Press CRTT to measure aggressive behavior: the unstandardized use of the competitive reaction time task in aggression research.

The competitive reaction time task (CRTT) is the measure of aggressive behavior most commonly used in laboratory research. However, the test has been criticized for issues in standardization because there are many different test procedures and at least 13 variants to calculate a score for aggressive behavior. We compared the different published analyses of the CRTT using data from 3 different studies to scrutinize whether it would yield the same results. The comparisons revealed large differences in significance levels and effect sizes between analysis procedures, suggesting that the unstandardized use and analysis of the CRTT have substantial impacts on the results obtained, as well as their interpretations. Based on the outcome of our comparisons, we provide suggestions on how to address some of the issues associated with the CRTT, as well as a guideline for researchers studying aggressive behavior in the laboratory.

Problematic computer game use among adolescents, younger and older adults.

AIMS: Playing digital games has been associated with forms of addictive behavior. Past research on the subject has often been criticized on theoretical and empirical grounds, due mainly to measurement or sampling issues. The present study aims to overcome these two limitations, and presents data from a representative study in Germany using an already established instrument for measuring problematic game use. DESIGN: Large-scale, representative study using a computer-assisted telephone survey. SETTING: Germany. PARTICIPANTS: A total of 580 adolescents between 14 and 18 years of age, 1866 younger adults between 19-39 years and 1936 older adults aged 40 years and older (overall n = 4382). MEASUREMENTS: Problematic game use was measured with the Gaming Addiction Short Scale (GAS), which covers seven criteria including salience, withdrawal and conflicts. Additionally, differential aspects of personality, as well as gaming behaviour, were measured. FINDINGS: Only seven respondents [0.2%, 95% confidence interval (CI): 0.1, 0.3] met all criteria of the GAS Scale. In contrast, 3.7% (95% CI: 3.1, 4.3) of the respondents can be considered problematic users, meeting at least half these conditions. The percentage of problematic gamers among adolescents is above average (7.6%, 95% CI: 5.6, 10.1). High GAS scores are associated with aggression, low sociability and self-efficacy and lower satisfaction with life. Additionally, these scores correspond with intensive use and preferences for certain gaming genres across all age groups. CONCLUSIONS: Following Gaming Addiction Short Scale criteria, gaming addiction is currently not a widespread phenomenon among adolescents and adults in Germany. Gaming Addiction Short Scale scores are associated with intensive use, as well as certain problematic aspects of individuals' personalities and social lives.