Discuss how the adoption of small family increase development

In those families, there is greater attention to family members, which helps them to develop better in the various aspects.

Explanation: In those small families, parents can usually take more care of their children. That is, parents can be better involved in the various learning processes of the child. This also contributes to a more stable economy in the family since for each child there is an expense, and in general parents want to give the best to their children so that they grow up in the best possible way.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.