In decision making, people may rely on their own information as well as oninformation from external sources, such as family members, peers, or experts.The current study investigated how these types of information are used bycomparing four decision strategies: 1) an internal strategy that relies solelyon own information; 2) an external strategy that relies solely on theinformation from an external source; 3) a sequential strategy that relies oninformation from an external source only after own information is deemedinadequate; 4) an integrative strategy that relies on an integration of bothtypes of information. Of specific interest were individual and developmentaldifferences in strategy use. Strategy use was examined via Bayesian hierarchicalmixture model analysis. A visual decision task was administered to children andyoung adolescents (N=305, ages 9–14). Individual differences but noage-related changes were observed in either decision accuracy or strategy use.The internal strategy was dominant across ages, followed by the integrative andsequential strategy, respectively, while the external strategy was extremelyrare. This suggests a reluctance to rely entirely on information provided byexternal sources. We conclude that there are individual differences but notdevelopmental changes in strategy use pertaining to perceptual decision-makingin 9- through 14-year-olds. Generalizability of these findings is discussed withregard to different forms of social influence and varying perceptions of theexternal source. This study provides stepping stones in better understanding andmodeling decision making processes in the presence of both internal and externalinformation.