The Role of Congruent Sibling Pubertal Maturation in Similarities of Risky Behavior

• In Event: 1-012 - The Impact of Siblings on Problem Behavior among Adolescents

Integrative Statement

Extant research documents that sibling age-spacing is consistent moderator of the associations between older and younger siblings’ attitudes and behaviors (e.g., Harper et al., 2016; Samek, et al., 2015). Specifically, siblings tend to be more similar when they are closer in age (e.g., Rowe & Gulley, 1992; Samek & Rueter, 2011). Post hoc explanations for this pattern of findings often focus on shared environmental factors, such as increased social connections. However, it is possible that pubertal maturation is a more salient measure of developmental similarity than age. To our knowledge, none have considered pubertal maturation. Puberty is characterized by a torrent of morphological, physiological, and behavioral changes that are associated with increased risk-taking (Braams et al., 2015), as well as transitions in neural development and cognition (Juraska & Wiling, 2017). Given normative age-spacing in sibling dyads (2-3 years), the congruence of sibling’s pubertal status may be an especially salient context during adolescence, when pubertal development is ongoing, because siblings are treated similarly/differently based on appearance, or physiological changes and brain maturation. Thus, the current study investigated whether differences in siblings’ pubertal status moderated the associations between their risky behaviors. We hypothesized that siblings’ with more similar pubertal maturation would be more similar in their risky behavior.
Utilizing two datasets with identical protocols for measuring key study variables, a sample of older siblings (M = 15.71, SD = 1.07 years old) and younger siblings (M = 13.18, SD = 1.29 years old) were analyzed (N = 391 sibling pairs). Adolescents completed questionnaires reporting on their pubertal development (PDS; Petersen et al., 1988) and their participation in risky behaviors (Eccles & Barber, 1991). Difference scores between siblings’ reports of pubertal status were created to index similarity in pubertal stage. Age-spacing and sibling dyad gender composition (0 = same-gender dyad; 1 = mixed-gender dyad) were included as control variables.
Utilizing hierarchical multiple regression, younger siblings’ risky behaviors were regressed on older siblings’ risky behavior, pubertal status difference score, and an interaction of sibling puberty status difference and older siblings’ risky behaviors, controlling for chronological age-difference and gender composition. As seen in Table 1, there were main effects of sibling age difference (β = - .17, p< .001) and older sibling risky behaviors’ (β = .26, p < .001) on younger siblings’ risky behaviors. Above and beyond sibling age difference, there also was a main effect of sibling pubertal status difference (β = - .12, p = 0.01). These main effects, however, were qualified by a significant interaction between older siblings’ risky behaviors and pubertal difference (β = - .16, p < .001). As can be seen in Figure 1, there was a positive association between older and younger siblings’ risky behaviors for youth who were more similar in pubertal stage. However, when siblings were more disparate in pubertal stage, there was no association between siblings’ risky behaviors. These findings provide evidence that pubertal maturation is a relevant context, beyond sibling age difference, for assessing similarities or differences in sibling behavior and development.

Authors

• Emily Rolan, Purdue University
  Presenting Author

• Shawn D. Whiteman, Utah State University
  Non-Presenting Author

• Kristine Marceau, Purdue University
  Non-Presenting Author

• Susan M. McHale, The Pennsylvania State University
  Non-Presenting Author