The origine of human psiquic activities (language, intelligence, capability to maje artefacts, etc.) has traditionally been looked for either in human soul singularities or inside it. There was also the explanation of the origine of the conscious activity as a singular fact of the homo gender. Nevertheless, as hominids are social beings and they show evidence of some superior psiquic activity, we must look for the roots of this psiquic activity in the common evolution of hominids and their habitat, since this was what determined their diversification and dispersion according to the coherent interaction among the different levels of action (level of intervention, level of perception and level of representation). In this article we claim that language and thought, as systems to represent nature, and the elaboration of artefacts, as a way to interfere in nature determined by the systems of representation, are the product of the own work of each species.