We are not private individuals, as we may think. Even when we are a quite alone, in our minds, thousands of voices and outside influences are continuously determining what are we going to think or how are we going to behave. Among those voices, we will find our mother or father, our long-forgotten distant relative, or a friend from childhood all telling us and expressing their opinions on how we ought to behave.
In return, we do the same, expressing our opinions and making our mark on them. Even if they don't believe us and do not trust our judgment, regardless, they will pay very serious attention to it. By the nature of the mind and information flow, they just can't help it. As a result of this cacophony, we all are averaging our group behaviour within our socially-connected groups.
American psychologist, author, and inventor B. F. Skinner had a habit of conducting a behavioural experiment in his classroom *1. First, he would arbitrary select two members of the class and send them outside of the room.
Then, he would position two chairs and label them with A and B, and he would instruct the class that, when the selected members return to room, he is going to engage them in conversation, and the class needs to agree with A, regardless of what he says, and to disagree with B, regardless of what he says.
When the selected students came back into the room, they took their seats, and the conversation began. It may happen that person B could be a very strong-minded and articulate person, and person A really incompetent; however, what happens is that, by this group agreement A being agreed on every point becomes encouraged and uplifted, and he becomes more articulate and finds himself blooming. Person B, by being disagreed with on every point, begins to get baffled, confused, and starts to feel very uncomfortable.
Unless, person B is on the top of his game and challenges the whole group. By understanding that the group has a collective agreement to disagree with everything he says, he obtains an advantage over the group by renouncing their opinions as invalid, paying no attention to them.
Psychologist George Herbert Mead has emphasised the distinction between the "I" and the "me." The "me" is the accumulated understanding of "the generalized other" (i.e. how one thinks one's group perceives oneself) *2. In that sense, the mind is the structure that imports the social process. By it, we are becoming the sum total of all the things that people have told us and that we have received trough our senses. In this feedback loop between our “personal self” and society, we gain the reflection necessary for our self-realization.
We are influenced by each other, and our individuality is rather an expression of a social network than the solitary being.
Deliberately harnessing these processes can equally lead to good or bad outcomes from the perspective of the society or an individual. In one sense, people can be brainwashed to justify otherwise morally unacceptable actions; and in other sense by the same mechanism, they could become a cohesive group, without barriers, all cooperating and loving each other.