Yes, it is integral component of behaviour

I think that if anything th new field of economics known as conductual economy has shown tow things: first that there is no such void between social sciences as some authors say, and two that there are better and more robust ways to explain the human behavior that is much more complex that the neoclassic theory portrait. You mention Smith and it was truly his idea in the first place, but there are other economists and economic branches that came to the same conclusion Keynes for instance in his general theory of employment, interest and money. Also the institucional economy has many debts not only with psycology but also with sociology and anthropology. The ultimate approach to explain the human behaviour in a credible way would necessarily need to be a multidimensional approach that combines all social sciences.

Behavioral Economics as a field received a boost when Richard Thaler got a Nobel Prize in Economics in 2017. It is really about the psychology of making economic decisions--especially bad ones. In popular articles, Thaler referred to the issue of putting off unpopular decisions like the need to increase personal savings to stave off debt or spending less on healthier foods, even when less expensive, when the benefits are well known. The "fork in the road" in terms of career development could also be a result of psychological considerations as much as it would be an attempt to maximize lifetime earnings and welfare.

To add to the answer from Kayizzi-Mugerwa I suggest looking at Thaler, Richard and Cass Sunstein, "Nudge," Penguin, 2009 and Thaler, Richard, "Misbehaving"