Many individuals today believe that ethical behavior is determined by what is best for them at the time. This is an example of

egoism, egotism, individualism, narcissism

Explanation: these four words are not 100% synonymous but they correspond with what you are talking about. All of them are (of course) culturally, socially and historically conditionedit means that they do not result 100% from psychological (innate) conditioning.

answertime between the cs and us;