Neuroevolutionary and Psychosocial Mechanisms of Permissive Grandparenting: A Systematic Review of Primary Empirical Evidence

Abstract

The phenomenon of changing parenting behaviors, in which authoritarian parents transform into permissive ("indulgent") grandparents, is a significant adaptive paradox. This study aims to investigate the neurobiological, evolutionary, and psychosocial mechanisms underlying this shift through a synthesis of primary empirical studies. Using a Systematic Search and review approach to primary literature (2019–2025) from the Scopus and PubMed databases, this study selected nine key empirical studies (n = 9) that met strict exclusion criteria for secondary review articles. The analysis identified three main mechanisms: (1) Neurobiological: fMRI and structural MRI studies prove that interaction with grandchildren activates dopaminergic motivational circuits and reduces the brain age of grandmothers by up to 5.5 years; (2) Evolutionary: Genealogical analysis shows a shift in roles from "survival support" to "fertility facilitator" as demographics transition; and (3) Psychosocial: Latent Profile Analysis (LPA) reveals that inconsistent parenting patterns (positive grandparents/negative parents) are a risk profile, but grandparents' motivations are consistent with Socioemotional Selectivity Theory (SST) to prioritize current emotional satisfaction. It is concluded that grandparents' "soft" attitude is a biological adaptation for neuroprotection and an emotional regulation strategy in old age, not merely a decline in discipline.