In a microgenetic study, a researcher and colleagues wanted to know how transitioning from crawling to walking affected toddlers' interactions with their physical and social environment. The researchers placed cameras on the heads of crawling infants who they thought were on the verge of learning to walk and studied the resulting daily recordings before, during, and after the transition, over a period of weeks. They found that crawling infants looked more at the floor and their own hands than at other people or objects, but the more they walked, the more they were able to look at people's faces and at physical objects near and far, thus learning more about the physical and social world. They were also able to carry objects to people and initiate interactions more.

Explain how you know this study is microgenetic rather than longitudinal or cross-sectional. Be sure to include the purpose of the study as part of your explanation, and how that purpose contrasts with the purposes of longitudinal or cross-sectional studies.

incorporate an explanation of why a microgenetic design is appropriate for this research question but a longitudinal or cross-sectional one is not.