A PRISMA-Based Systematic Review of Behavioral Biases and Demographic Moderators in Investment Decision-Making

Behavioral finance challenges classical rational-investor models by demonstrating that psychological biases shape financial decisions. Evidence indicates that overconfidence, herding, loss aversion, and the disposition effect are not uniformly distributed but are shaped by gender, age, financial literacy, income, and investment experience. However, the literature remains fragmented across contexts and geographies. This PRISMA 2020 systematic review synthesizes 57 empirical studies (2010–2025) screened from 172 Scopus records and appraised against eight quality criteria. Findings confirm overconfidence (31 studies) and herding (26) as the most prevalent biases, concentrated among younger, male, and less experienced investors, whereas loss and risk aversion are more common among female, older, and financially insecure investors. Financial literacy emerges as the strongest moderator, reducing most biases while paradoxically amplifying overconfidence at moderate levels, consistent with the Dunning–Kruger effect. Formal moderation analyses (14 studies) support literacy as a significant boundary condition, and investment experience exhibits a non-linear pattern favoring moderate levels. This review contributes a structured, quality-appraised synthesis and a research agenda addressing intersectionality, longitudinal designs, and geographic diversity.