Re economists assumptions of utility or profit maximization good approximations of real peoples behavior?

Are economists assumptions of utility or profit maximization good approximations of real peoples behavior? From my question, I will try and find some articles and bibliographies that talk about how economists are really relying on peopleas behavior or not. Or are they just relying on their own perspectives and understanding of people. Also upon my research I will ask about how economists measure their assumptions, and if they are really accurate or not. Tie it to the economical behavioral and economist behavioral. How they really look at it. Age and their experiments. 1000 words at least. 5 academic resources. APA Style format