To study the relationship between the education of offspring and the developmental trajectory of cognitive function in the rural elderly, and to explore the mediating effect of intergenerational support.

Based on seven waves of a special longitudinal survey spanning 18 years, a group-based trajectory model was used to identify the heterogeneous developmental trends of cognitive function in the rural elderly population. An unordered polytomous logistic regression was employed to study the association between offspring’s education and the developmental trajectory cognitive function among the rural elderly. The KHB method was utilized to analyze the mediating effect of intergenerational support.

A total of 1 342 elderly individuals, aged 60 to 100 years and having participated in at least two survey waves, were included. Three cognitive function trajectory groups were identified: the low decline group (19.75%), the moderate decline group (44.41%), and the high stability group (35.84%). Compared with subjects in the low decline group, those with higher levels of offspring education were more likely to belong to the moderate decline or high stability groups. Intergenerational support played a significant mediating role in this relationship, exhibiting a characteristic of need dependency. Furthermore, intergenerational economic support contributed the most to the mediating effect in each trajectory group, and robustness checks yielded similar results.

There is heterogeneity in the trajectories of cognitive function among the rural elderly. The educational achievements of offspring are an intrinsic driving force for the positive development of cognitive function in this demographic. At the same time, under the continuous impact of modern ideas and cultural waves, the traditional "filial piety culture" in rural areas of China remains deeply rooted.