That is Paul Zak’s theory. The video is fascinating:
Now I just need to find 8 people to hug me everyday.
(via Philosopher’s Haze, who you can read for a summary if you cannot watch the video for some reason).
Patricia Churchland’s book Braintrust: What Neuroscience Tells Us about Morality explores the role of Oxycotin in morality in some depth too.
And, on the flip side of all of this, for a brief overview of the ways the brain, region by region, can malfunction morally, check out Anatomy Of A Psychopath : The Neurobiological Basis Of Evil.