To determine whether piaget's stages are universal, brad and greg conduct a research project in which 20 children in the united states and 20 children in ireland complete several conservation tasks. they are conducting a study.

They are conductin a comparative study.

Explanation:

Comparative research is a methodology used to compare results accross different populations. In this case, Brad and Greg have chosen two different countries, United States and Ireland, in order to compare results and verify if Piaget's theory can be generalized and taken as universal. Comparative research allows researchers to analize variables that vary from one culture to another and that are a result of social and cultural environments that corresond to a specific time and space.

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