Coinciding the features of emerging adulthood with the traits of the second demographic transition: Prominent spatial patterns in developed countries

The study of emerging adulthood (EA) has grown alongside the developments associated with the second demographic transition (SDT). This study examined the components of SDT that align with emerging adulthood (EA) features and their patterns across developed countries. We used the OECD family database of 22 developed countries, drawing on measurable indicators representing SDT and EA—which are not directly quantifiable—and performed a hierarchical cluster analysis to examine their relationship. The result reveal that emerging adults' features align with various components of SDT (e.g., marriage age, premarital cohabitation, and single living). Finally, looking at how the components of SDT appear together, four patterns of emerging adults’ behavior are identified: transitioning, oscillating, extensive, and little to transition. For future extension of EA theory and research, the integration of SDT components and EA features needs to be synthesized using both approaches and refined further based on their applications over diverse regions. • Emerging adults' features meet with SDT's different components. • Four types of patterns of emerging adult behavior detected in a set of 22 developed countries. • The patterns of SDT and its relationship with emerging adulthood was dominated by the transitioning SDT pattern. • Little to Transition pattern is least transition in terms of relationship between SDT and EA. • European regions show different patterns, highlighting the complexity and context-specificity of demographic processes.