A hypothetical example of how many people do not understand the relationship between culture and human behavior

 What if all the rules of Japanese culture (including even learning the language) were imposed on Brazilians who are being born now, from their first years of life???

Would they become "culturally Japanese"??

Depending on which Brazilians we are talking about, it is likely that there would be a variable cultural change. And, in general, it is also likely that non-significant changes would occur. Therefore, yes, the environment influences human behavior. But this influence is not absolute or predominant. First, for there to be a reaction of adherence to a certain social or environmental pressure, there must always be a predisposition, so it is safe to say that no behavior is possible without an underlying (biological) possibility or potential. Second, the generation of Brazilians who were subjected to this experiment is unlikely to replicate the typical behaviors of the Japanese, or of the original culture, since we are dealing with two distinct populations, cognitively and psychologically. So, even if the cultural bases were the same, the average and most intrinsic characteristics of the two populations would contribute to altering the final result, in the sense that the "culturally Japaneseized" Brazilians would not become exact copies of the original Japanese and, even though we are dealing with such distinct populations, another type of culture, more intermediate, but also more possibly closer to Brazilian culture than to Japanese, would emerge... But this is not what many people think, since they believe precisely in the determinism of culture or the environment (a flat-eartherism of behavior) and not of biology, that, if a certain population receives a certain education, it, for the most part, will behave completely accordingly, believing that the differences between an average Japanese and an average Brazilian are only cultural and not that they are reflections of their most intrinsic behavioral dispositions and also that, in the same way that Brazilians can be fully educated like Japanese, the opposite would also be possible, another type of flat-eartherism of behavior, of the indefinite or infinite adaptive plasticity of the human being, as if our psychological and cognitive limits/potentials were completely alterable or surmountable.