Humans have much more sophisticated communication skills than other species. They are not limited to emotional cries, alarm calls and soothing demands, but they interpret the inner and outer world in a symbolic way, resulting in a collective intelligence and an accumulation of knowledge called culture. This culture permeates the child and fosters efficient learning, based on the knowledge accumulated through generations. To develop this collective intelligence, it requires (1) a social brain predisposed to learn from conspecifics, (2) awareness of one's mental state and knowledge, and those of others, (3) a shared common language of though, (4) a communication system for exchanging this information. In this essay, we insist on the value of symbolic representations as a compressed necessary format for representing information to ourselves and exchanging information with others. We propose that human cognition has been boosted beyond the cognition of other primates by the multiplicative advantage of co-development of social cognition, language but also symbolic thinking that can be observed from the first months of life on.