Our transition from vulnerable primates to the most powerful species on our planet was due to group survival strategies which at times could have had a significant cost to the individual. For example, someone who warned their group of approaching predators by making a loud sound would risk attracting the attention of the predator. Another example involves the evolution of the large white areas in our eyes with contrasting dark pupils. These allowed humans to communicate through a dyadic gaze calling another’s attention to a threat or a food source. This feature however also comes at a cost.
If an individual indicated that they located some berries they would probably have to share them, doing so, however, obviously enhanced the survival and reproductive success of our white eyed, cooperative ancestors. Animals with less contrasting eyes have superior concealment, but to better signal their thoughts and intentions to others, humans sacrificed camouflage for communication.
Humans are also neurologically built for cooperating and caring for each other. When we commit acts of kindness, our brains get a pleasurable rush of neurochemicals which can include endorphins, serotonin, dopamine, and oxytocin. Social isolation seems to register in the same regions of our brain as does physical pain. Human brains also have mirror neurons which fire when we observe the behavior of others, similarly suggesting that we have evolved to be highly sensitive to each other. While mirror neurons are also present in some other animals such as macaques and songbirds, the mirror neuron system in humans is particularly well developed.
Healthy humans naturally possess an extended sense of self-interest. Imagine being on a bus seated behind a parent treating a child with patience, attention, and kindness. Most people are likely to feel pleased and comforted — a natural empathetic reaction. If, however, the parent was unresponsive, or threatening to the child, most people would probably feel diminished, sad, or frustrated.
Undoubtedly, some who encounter such scenes might feel very little if they have had their natural sensitivity reduced resulting from the insufficient support of their developmental needs, or having to cope with an overly stressful environment.
As we desperately try to get what we need, like plants turning toward or away from the sun, humans will also twist and turn as necessary. While capable of being sensitive to the most subtle and diverse range of stimuli of any living being we know, humans will also toughen as much as their environment requires, adjusting how and what they will respond to. When circumstances cause a person to twist and toughen, the way their human potential is expressed may become severely distorted, and in extreme cases can result in inexplicable behavior such as in mass shootings, sexual violence, and torture. Observers may feel compelled to evoke supernatural causes, attributing such behavior to “pure evil.” Unfortunately, such labeling offers no utility.
The ultra-social behavior we can expect from mature and healthy members of our species is entirely contingent upon their inheritance of healthy genes along with essential developmental support.