Cognitive Development: Cognitive development refers to the progressive growth and maturation of various mental processes such as perception, attention, memory, language, problem-solving, and decision-making abilities in humans.
Longitudinal Study: A longitudinal study is a research design that follows a group of participants over an extended period to observe changes or trends in variables of interest. In this case, it would involve tracking individuals' early childhood nutrition and later assessing their cognitive abilities.
Experimental Group: In experimental research, an experimental group consists of participants who receive a specific intervention or treatment under investigation. In this context, it could refer to individuals who are provided with controlled early childhood nutrition while being compared to other groups receiving different interventions or no interventions at all.