Tonia Davenport published a quiz from Malcolm Godwin's book "Who Are You? 101 Ways of Seeing Yourself" that scores your oxytocin level. For example, if you feel less attracted to someone after making love, your body didn't feel that oxytocin rush; on the other hand, if you feel even closer to the person afterward, you've got your OT on.
Our brains are constantly recreating an inner model or the actual world around us.
And that world is strongly influenced by our biochemical tendencies (as well as our life experiences.)