oupacademic:

According to Dr. Donald Pfaff, author of

The Altruistic Brain: How We Are Naturally Good, every time we register the need to perform a selfless or benevolent act, our brains undergo a five step process within a few hundredths of a second after our recognition of the need to act. Pfaff argues that this process, referred to as Altruistic Brain Theory (ABT), activates humans’ predisposition to act altruistically.

The 5 steps of ABT:
Step 1: Representation of what the person is about to do
Step 2: Perception of the individual toward whom the benefactor will act
Step 3: Merge images of the victim with one’s own self image
Step 4: Activation of the altruistic brain by feelings that allow the benefactor to assess potential consequences
Step 5: Performance of an altruistic act