Just like medical illness/health, a combination of internal predisposition, external circumstances, and their interaction. The contribution of each would depends on the particular behavior.
a first, simple answer to your question is: nothing! A second answer, since your questioning appears always when we try to inquire the countless problems raised by the so diverse human decisions and behaviors is an infinite number of factors. As expected of a set with infinite elements (literally) this could be seen as a refutation of your terms "determines, reveals and directs". All we may state about the determinants of a human decision are probability sets, based on his/her, or even others' decisions. Doesn't it look like the behavior of electrons, as stated by Heisenberg Uncertainty Principle?
In any given circumstances, an evolved and adopted coherent value system somewhat determines, reveals, and directs human behaviors as a response or reaction expressed through a wise or poor decision making.
I think family moral values play the key factor determining human behavior. Besides education system, social values and religious values also are very important.
Free will or choice is guided by false or right human assumptions (intentions), with reference to situation and goals, i.e. values (preferences) do matter for all informed guesses in our limited life time (the real budget).
Wow. That's a big question. It's almost 'What is the meaning of life?'
My suggestion is that you should read Jonathan Haidt's book, 'The Righteous Mind' (Penguin). The Kindle edition is very cheap. There are also various YouTube items etc. that will come up if you Google the book.
There is a duality of mind and body. One might also class these as mind and material. I repeat mind because phenomena such as the spiritual, thoughts, identity, the nonmaterial, are included. Human behavior is determined and directed by the duality itself.
If we are conscious and with free will, with free choice, then mind directs our behavior from its experience of body and, paradoxically, of mind itself. We experience the world and ourselves and direct our behavior according to both.
Keep in mind that the behavior of other conscious beings can change and direct our own behavior. So there is again a paradox of mind as an emerging condition of our shared selves.
You look, you see, you act, and the world acts back. By this you are changed and your looking, seeing, and acting evolve. And so your mind and body are not singular things. Your identity is an illusion of permanence. This is the paradox of the identity of mind. This is the paradox of the identity of body.
And by extension, if this philosophy or other philosophies reveals your self to you, you are again changed and evolve.
Intuitions are important influential, even when we rationalise them ex post. So it's worth exploring where intuitions come from.
Are they innate? Some are, (e.g. flight or fight).
Or are they learned as we grow up in particular cultures? Some are (e.g what family groups do we come to regard (automatically) as normal?).
Jonathan Haidt's work (mentiuoned in my previous post) is a good way to get into this sort of thing. See also: Stephen Pinker, The Stuff of Thought: Language as a Window into Human Nature (New York: Penguin, 2008) 229-234; Peter Singer, ‘Ethics and Intuitions’ (2005) 9 Journal of Ethics 331-352; and Joshua Greene, Moral Tribes: Emotion, Reason and the Gap Between Us and Them (London: Atlantic Books, 2014).
Fate. At the same time, a person mistakenly thinks that he has free will. But his free decisions are rigidly predetermined. Usually people think like in the posts above. But these messages are also rigidly predetermined. At the same time, the people who write them mistakenly think that they write them of their own free will.
Each person is in a place and time and does what he needs most for his further evolution. And everything else: genes, society and education are all consequences
Article UNIVERSAL INFORMATION VARIATIONAL LAW OF SYSTEM DEVELOPMENT
There are several determinants of human behavior, including: the educational stage, the cultural level, social affiliations, ethnic and sectarian, hobbies, scientific and professional specialization, community education, prevailing customs in society, income situation, health or physical condition, age, gender ... and others.
Considering empiricism, Individual is shaped by all the experiences gained with the passage of time. The origin of those experiences can vary according to the social contacts that he/she develops. for instance, it can be drawn from the history of the society and beliefs thereby.
However, it is necessary for an individual to filter out the best out of them and define his/her morality.