The Frontal Lobes are the very latest evolutionary addition to the Central Nervous System. If the brain were stretched out into a long tube, they would be at the very front end. In humans they are very well-developed and comparatively large. The skull has expanded to accommodate them, which gives us our large protuberant forehead. I imagine that to apes, and our distant ancestors, we must look like those weird aliens on Star Trek with those bulbous foreheads.
The Cerebral Cortex (including the Frontal Lobes) takes up about 80% of our brain space, compared to 60% in monkeys, and less and less down the evolutionary tree.
It appears that the Frontal Lobes are crucial to our higher functioning as humans, and people with Frontal Lobe damage are often impaired in their ability to judge others’ motivation, are prone to deception, may be less sympathetic to others and may have reduced capacity for empathy, to appreciate humour and perceive sarcasm. They may become sexually disinhibited, apathetic, lack motivation, and indifferent to the suffering of others.
It seems the Frontal Lobes are the place from which we do compassion, gratitude and forgiveness. It may also be the location for our other higher capacities, such as tolerance, justice, ethics, morality and so on. It appear s that practising meditation on loving-kindness, love for others (eventually even including our enemies), wishing joy for ourselves and others, and forgiving ourselves and others, increases the number of cells and their connections in the Frontal Lobes and to the rest of the brain.
Some of these connections feed back to the Amygdala (which is the paired structure which does the fight and flight reaction). This calms the entire Limbic System down. We become less prone to all those negative emotions generated by the Limbic System, such as fear, anger, greed and lust. Which is nice.