Independent Variable: This refers to the variable that is manipulated by researchers in an experiment. For example, in this scenario, it would be the specific sensorimotor activities being performed by toddlers.
Dependent Variable: The dependent variable is what researchers measure or observe to determine if there's any change or effect caused by the independent variable. In this case, it would be cognitive development in toddlers.
Control Group: A control group is a group within an experiment that does not receive any treatment or intervention. It serves as a baseline for comparison with other groups receiving different treatments or interventions.