Eine Studie in 237 Ländern zeigt, warum die Geburtenrate sinkt

A groundbreaking study examining over 200 years of demographic data from 237 countries has identified a consistent pattern behind the global decline in birth rates. Researchers analyzed historical records dating back to 1800 and found that despite vast differences in culture, politics, and geography, nations tend to follow one of two common pathways as fertility declines and life expectancy increases. The findings were published in the journal Evolutionary Human Sciences and challenge previous assumptions that demographic transitions depend largely on local conditions. The study highlights how demographic transition, the process through which societies move from high birth and death rates to lower ones, is influenced by universal mechanisms rather than unique national circumstances. This transition has traditionally been linked to modernization, with mortality rates decreasing first, followed by a decline in fertility. However, the research suggests that education plays a pivotal role in shaping this shift. Kenji Itao, a researcher at the RIKEN Center for Brain Science in Japan, emphasized the impact of educational systems on family decisions. He noted that in highly competitive academic environments, parents often face pressure to allocate substantial time and money to each child's education. According to Itao, this increased investment in individual children can make having additional offspring financially unfeasible. "It is crucial to reduce the financial burden of education on households to recover fertility during the education-intensive Phase II," Itao stated. He explained that resources intended for raising multiple children could instead be funneled into enhancing the prospects of a single child, such as through private tutoring and other educational expenditures. Governments around the world are exploring strategies to counteract declining birth rates, yet Itao cautioned that his research does not directly assess the efficacy of particular policies. Nevertheless, he referenced recent initiatives in China and South Korea aimed at mitigating intense educational competition and diminishing dependence on private tutoring. These measures, according to Itao, warrant close observation to determine if they lead to reduced household educational spending and a subsequent rise in fertility rates. The study investigated the correlation between crude birth rates and life expectancy across more than two centuries of global demographic data. Its analysis unveiled two predominant phases that recur across different countries. The initial phase, prevalent until approximately the mid-20th century, featured high child mortality and sustained population growth. During this era, countries generally adhered to a pattern where fertility and life expectancy evolved in tandem, preserving a relatively stable relationship. The second phase began around 1950 and has since become the prevailing trend globally. Characterized by low child mortality, rising life expectancy, and ongoing economic progress, this stage is accompanied by falling birth rates. Most countries either adhere to one of these trajectories or evolve from the first to the second as they advance economically. To elucidate the observed trends, the researchers formulated a theoretical model grounded in the trade-off between the quantity of children families have and the level of investment in each child's education. As education gains importance for economic achievement, parents may opt for fewer children while channeling more resources into each one. The model indicates that various elements can hasten the shift to the second phase, including reduced educational costs, enhanced social mobility, and cultural shifts tied to modernization and Western influence. Itao clarified that the study does not advocate against education itself, acknowledging its critical role in societal advancement. "Mass public education represents one of the major accomplishments of modernization," Itao remarked. "A well-educated populace is vital for fostering innovation necessary for societies to adapt to aging populations and shrinking labor forces." He suggested that offering accessible, high-quality public education to wide segments of the population might enable societies to sustain the benefits of both education and adequate fertility levels.