It's a little nebulous to say, but no less true that a primary attribute of what a human is in evolutionary and behavioral terms is self-awareness. I'm sure that means many things, some of which would be hard to put into words, but this orients around one main meaning. It is like the larger theme of this story that humans need to add to or replace the strategies that nature has given us. Life tends to work on as a stimulus-response mechanism. Humans need to decide what their response will be. They need to plan instead of reacting. It's also something larger about consciousness, but that comes with it and is hard to describe. It is something that can "be left to the reader".
There is an indication of this in evolution. It appears that about 130,000 years ago a mutation appeared that effects the parietal lobe. The parietal lobe maps the body. If it is injured, you may decide that your arm doesn't belong to you. It seems weird, but studies of brain injuries show this. It also helps you map where you are in your environment. It seems that it allows you to abstract your self. Very rapid human development followed this. Current speculation includes that this ability to abstract oneself led too much of our intellectual and cultural development. It would probably be best called Self-Awareness.
This discussion is less about a particular survival strategy than it is about using human strategies. Self-awareness is not unique to humans. Just hang around horses for a while and you will know that, but human self-awareness seems to let us abstract more and that made our present and is critical to our future. This describes what seems to be the evolutionary source of increased human self-awareness but focuses more on practices that help develop self-awareness. Some of this comes from philosophy. Stoic philosophy describes making a habit of planning your daily actions and evaluating them at the end of the day. It's efficient, but more importantly, it drives self-awareness. The same is true of consciously imitating your chosen heroes and asking what they would do in your place. It not only helps you make better decisions, but it also trains your objective self-awareness. To be self-aware is to be human.
Another way to train self-awareness is by training your body. The mind body link is powerful. It can even be enhanced by learning breath control techniques.