Co-rumination cultivates anxiety: a genetically informed study of friend influence during early adolescence.

This study tested 2 related hypotheses. The first holds that high co-rumination anticipates heightened internalizing problems. The second holds that positive relationships with friends exacerbate the risk for internalizing problems arising from co-rumination. A sample of MZ twins followed from birth (194 girls and 170 boys) completed (a) self-reports of friendship support, friendship negativity, and co-rumination with friends at age 12 and (b) measures of anxiety and depression at ages 12 and 13. Using a monozygotic twins-difference design, within-pair differences in co-rumination predicted increased within-pair differences in anxiety (but not depression), after removing the covariance between co-rumination and perceptions of friendship. In other words, the difference in co-rumination within each monozygotic twin pair predicted an increase in the difference in their anxiety levels, but not the difference in their depression levels. The discussion focuses on nonshared environmental influences, because the monozygotic twin-difference design eliminates the possibility that associations were driven by heritability or by shared environmental factors that underlie friendship experiences and internalizing problems.

Self-reported rates of interpersonal conflict vary as a function of questionnaire format: why age-related trends in disagreement (and other events) may not be what they seem.

Two studies examine whether self-reports of interpersonal conflict differ as a function of how the question is asked. In Study 1, 56 U.S. college students (M = 20.7 years) completed different versions of a questionnaire, four times, at one week intervals. Participants reported more conflicts with the aid of memory prompts than without, an effect that was especially strong when questions focused on events from the previous day. In Study 2, 123 middle-school students (M = 11.08 years) and 128 primary school students (M = 8.2 years) from the same region completed one of two questionnaires describing conflict during the previous day. Children reported more conflicts with memory prompts than without. The effect was twice as strong for younger children than older children. The findings suggest that increases in reports of conflict across the transition into adolescence may be due to improvements in the ability to recall and recount events in the absence of memory cues.