Baby kai has an easy, cheerful disposition. as a result, adults are likely to engage in positive interactions with kai, which will strengthen his cheerful disposition and motivate him to smile and interact more. this example illustrates that development is

I believe the answer is : bidirectional development

bidirectional development refers to a type of development that affect both parents and the children as the interraction between them occurs. The most common bidirectional development would be the parents tend to be more responsible and discpline after having kids while the children would learn many various new things from the more experienced and knowledgable parents.