This question recently came my way, with the questioner admitting that although they thought they knew, on thinking about it, they finally felt they had no idea.
So here is my attempt to shed some light. Sorry if it just looks like I’ve thrown mud all over it.
There are two levels we can define a human behaviour: functional (the what) and physiological (the why). Ego is a term for a functional level. Specifically the ego is the habitual emotional and behavioural response to any event.
As to the why. We can consider that our fundamental psychology is based on the evolutionary development of the brain in 3 phases: reptilian, mammalian, and human. The first two phases provide us with survival, namely killing and eating and avoiding being killed and eaten. Being good at this leads to access to procreation and propagation. Mutations which give an edge on this in any context (environment) create new species. Eventually we mutated a very large brain, a wonderfully agile opposable thumb, and a voice box, that together could really deliver hundreds of adaptive strategies to make sure we were very, very good at killing, eating and avoiding being killed. In exploring these possibilities, we mimicked the noises of the environment and, while that enabled us to become very fabulous team hunters and attractors of prey, we went beyond that to create speech and language.
Language has not only giving us an extraordinary ability to communicate with each other, it gave us the ability to talk to ourselves, to think. However, consider that our emotional birthright is to filter everything by its threat (could kill me) or reward (could be food), and provide rapid response. This is ego, and it is so rapidly responsive that every experience creates an emotional state that selects our response before we are consciously aware. This emotional response and action is reinforced from the earliest stages of life. As language develops in the child, it fundamentally co-exists with those emotional messages as a vehicle to kill (dominate) and avoid being killed (avoid domination). It’s responsiveness is reinforced either way by the experiences of the growing child.
The preponderance of our experiences and responses are through language with other humans. Our ‘human’ brain has become so extraordinary in its ability, through reiterative process, to have moved from simple mimicry to metaphor to the abstract though, that our rational consciousness seems to ‘float’ above, quite detached from, our physical nature. This is far from the reality. Our rational consciousness, playing catch up with our automatic response via the emotional-action system, usually just rationalises what we have done. However, if we become mindful of that initial emotional response, as we look at it which is happening through language, we will ‘hear’ ourselves translate that emotion into a ‘voice’. The little voice will be in one form or another be saying, “Let’s get out of here” or “I’m gonna kick your …” Of course it has been harping for so long while we build our rational faculties that it has become quite sophisticated itself. This older, subtler, ‘little’ voice has made choices for us from an early age, and from those choices we have created our identities.
Meanwhile, depending on the access, the human brain is exploring more abstract concepts. The abstract concepts such as mathematics and morals, are supported by the development of increasingly sophisticated language. So the little voice applies itself to the building of identity by using the individual best possibilities of the human brain to dominate others and avoid being dominated. In this manner, the ‘little’ voice can even mimic behaviour that looks like a ‘higher’ abstract concepts. In this way, it offers aggression as righteousness, hides rage in depression, and proffers withdrawal as humility.
Yet the big voice of the human brain has a trump card. It can look at itself and it can find and look at the little voice. But this is no easy task. As the little voice camouflages itself in so many ways, the human perception often slides off it. So responsive is our ego to any semblance of threat, it will equally respond to our more rational voice as an external threat, if that rational voice creates concepts of denial or suppression. Rather the way to quietening the ‘little’ voice is to accept it and look at it clearly. By avoiding denial of the ‘little’ voice, we talk with it out in the open, without it escaping into sophisticated mimicry. Then a simple acknowledgement, perhaps an enquiry about the ‘truth’ behind the emotional interpretation. Then a consideration about alternative possibilities to look at the event, which can induce alternate ways of feeling, and thus alternate responses. Here, higher order thought co-exists with lower order responses in a more reliable state for the development of higher order thought and behaviour. From this perspective we can see that, releasing the higher order thought through language from the little voice of ego has been a critical aspect of all spiritual teachings over time.