but very often they choose poorly, and if they do so, it is often because of evolutionary, or biological, or cultural forces which they may not even understand, or believe, are operating on them.
I submit that if you are aware of these subliminal influences you are better prepared to exercise your choices wisely. In other words, you act in your own best interests, not in accordance with some genetic imperative you haven't admitted to yourself exists, or which you even refuse to accept can affect you. A man who understands the reasons and causes of his emotional drives is much more likely to use his intellect to overide his physical urges to do something which in his circumstances might be totally inappropriate, like making a pass at his wife's sister.
And he who believes he never makes poor choices because he is too wise or virtuous to do so is setting himself up for a fall. The Greeks wrote countless plays about that particular quirk of human nature. They didn't know about evolution or psychology or cultural imperatives and biological drives, but they knew all about Destiny, the Fates and Hubris.
So they knew something was making them abandon their reason.