Mama vs. Granny: An Exploratory fMRI Study on the Relative Roles of Female Caregivers in Children's Cognitive and Emotional Outcomes.

Previous research on the relative roles of maternal and grandmaternal caregiving in child development has been limited by the "maternal advantage hypothesis" and the "grandmaternal advantage hypothesis". This study posited the "mother-grandmother relative advantage hypothesis" and aimed to evaluate the relative influence of maternal and grandmaternal caregiving in children's cognitive and emotional outcomes at both behavioral and neural levels. This study comprised two components. In Study 1, a total of 33 children from mother-led or grandmother-led caregiving families were asked to perform a working memory task, aiming to investigate the behavioral and neural differences in cognitive outcomes between the two caregiving groups. In Study 2, a total of 31 children from similar family backgrounds were asked to complete an emotional recognition task, which was designed to examine the behavioral and neural differences in emotional outcomes between the groups. At a behavioral level, grandmaternal rather than maternal caregiving was associated with children's working memory performance, whereas maternal rather than grandmaternal caregiving was associated with children's emotional recognition performance. At a neural level, compared to children in the grandmaternal caregiving group, those in the maternal caregiving group showed increased functional connectivity with the right middle frontal gyrus and the left superior frontal gyrus as seeds during working memory tasks and increased functional connectivity with the right inferior occipital gyrus and left precentral gyrus as seeds during emotional recognition tasks. Our findings reveal a complementary pattern of female caregiving effects, supporting "mother-grandmother relative advantage hypothesis".