When developmentalists use the term "expert," they usually mean a person who?

The term "expert" in the context of developmental psychology and other fields typically refers to a person who demonstrates a significantly higher level of skill or ability in a specific task compared to others. This definition highlights not just the accumulation of knowledge or years of practice, but rather the ability to apply that knowledge effectively and efficiently in practice.

While formal education and extensive practice can contribute to someone's expertise, they do not alone define what it means to be an expert. It is the combination of knowledge, experience, and superior performance in a particular domain that establishes someone as an expert. Thus, option B encapsulates the essence of expertise within the context of developmental psychology as it addresses the individual's ability to outperform others in a specific skill or area.