Answer:
cognitive
Step-by-step explanation:
Cognitive development: In psychology, cognitive development refers to the process of development in which a child figures out, thinks, and explores different things. It signifies the development of skills, dispositions, knowledge, and problem-solving that help a child to gain understanding about the world or surroundings around him or her.
A child's brain development is one of the parts of cognitive development. It focuses on the child's development of perceptual skills, conceptual resources, information-processing, language learning, etc.
In the question above, the given statement states that the researcher is interested in the cognitive-developmental area.