Dopamine levels can measure that effect, it is neither the cause or effect. It is like saying the salt in sea water is the active ingredient making fish live. Only certain fish, only one of the things required, and so on. “it” does not have influence on behaviour, “it” is a chemical used in many different parts of our brain, for instance used to keep us breathing among many other things also in animals and even plants, not affecting their behavior in any way.