This research provides a systematic overview of psychological areas using assimilation and accommodation to explain development and adaptation processes from 1998 to 2018. We primarily aimed to identify the main psychological research areas connected to assimilation and accommodation. We used assimilation and accommodation as keywords to extract data from SpringerLink, PsycINFO, and PsycARTICLES. Of 500 articles, 473 were included in the analysis. Ten categories were identified to allow systematization along with different research areas and development trajectories. The meanings of these terms were analyzed in terms of scientific impact, their connection to Piaget and Baldwin, application, and research methods. Our analysis has distilled the most driving and scientifically relevant approaches to assimilation and accommodation within psychological research, with the work of Baldwin and Piaget influencing practically all views. Thus, we have identified a common understanding of assimilation and accommodation, although the direction of the adaptation process should be made explicit in the future. Based on our analyses, we were able to identify white spots on the research map that should be focused on in future work: the need to better understand the interdependence and synchronicity of both processes, the connection to affects and emotions, and the potential co-research with artificial intelligence.