You seem to be referring to entirely different thing also called "behaviorism". One I talk about answers nature-vs-nurture by siding almost totally on the nurture side - it says virtually all variety of human behavior comes from different environments humans live in, not from them having different genes. The one you refer to is a particular theory of learning which is completely unrelated. It's not the only case of unrelated things having the same name.

Also, can you explain how you find twin studies "unconvincing"!?

Culture acts on genetic cues in arbitrary way. Let's say culture considers light skin higher status than dark skin. Then skin color genes will correlate ridiculously high with outcomes - and yet not a tiniest bit of this is genetic, it's 100% cultural effect. I see no value of any kind in such studies.

Similarly, religion is useful because it deludes people into believing they'll be punished for all misbehavior.

... and money is useful because it deludes people into believing they should work even though they could survive just fine with a lot less effort without working.

Our civilization is built upon such shared delusions.