Answer:
cognitive
Step-by-step explanation:
In psychology, cognitive development refers to the phenomenon that involves the way a child thinks, figure-out, and explore things. When a child encounters cognitive development then he or she gains the development of skills, dispositions, knowledge, and problem-solving technique which is responsible to help a child think rationally and in understanding the environmental surrounding around him or her.
Example of cognitive development includes brain development.
In reference to the question above, the researcher is interested in the cognitive development of the subject.