Spirituality is the path of Self-knowledge. If one comes to know the Self fully, then one knows all others as well...because at that point there are no "others" any longer. The other becomes the Self. That results in compassion, acceptance, and Love.

The life of Jesus is an outstanding example of the achievement of Self-knowledge and its resulting effects on the behaviour of one human being. The life of Buddha is another example of such. And there have certainly been others.

If you want a scientific analysis of the process, read some of Sri Aurobindo's writings. You'll need quite a bit of time and patience for that.