ABSTRACT
Among the most fruitful criteria for assessing phylogenetic evolution are the repertoires of action typical of a species, especially those modes that allow mastery over the milieu, whether it consists in using what the environment provides or in transforming it. In this respect techniques constructed by humans are not only rooted in acquired knowledge and culture, but they are also based on an individual psycho-biological exchange with the environment. From a psychological point of view, and because it is a universal need of organisms to interact with their environment, it is important to know how individuals acquire the status of an agent, i.e. how they generate observable effects consequent upon their own activity.
