Piaget believed that the appearance-reality distinction appeared at what age?

The answer is not until the age of 7 or 8
appearance-reality distinction  refers to the ability to see something like what it actually is rather than what it looks like.
According to piaget, most children belowe the age of 7 or 8 tend to misinterpret the two whcih limit their ability for decision-making process

The best sociological research method would have to be using experiments although it has some disadvantages as well