Tomasello also studies broader cognitive skills in a comparative light at the Wolfgang Köhler Primate Research Center in Leipzig.
Individuals need to make clear or explicit, by eye contact, by gestural pantomime or else, that they intend to coordinate their actions and perspectives under a common goal.
Tomasello's defense, use, and deepening of the shared attention and intention hypothesis rely on the experimental data he collected (see also work with Malinda Carpenter[8]).
Tomasello also resorts to an evolutionary two-step scenario (see below), and to philosophical concepts borrowed from Paul Grice, John Searle, Margaret Gilbert, Michael Bratman, and anthropologist Dan Sperber.
The heightened dependence on joint effort to gain food and the social selection of partners are supposed to account for an evolution toward better skills at coordinating individual's roles and perspectives under a common attentional frame (that of the hunt or scavenging) and under a common goal, giving rise to joint, interpersonal intention.
[11] For Tomasello, this two-step evolutionary path of macro-ecological pressures affecting micro-level skills in representation, inferences, and self-monitoring, does not hold because natural selection acts on internal mechanisms.
More broadly, Tomasello sees the sharing of attention and of intention as the roots of humans' cultural world (the roots of conventions, of group identity, of institutions): "Human reasoning, even when it is done internally with the self, is ... shot through and through with a kind of collective normativity in which the individual regulates her actions and thinking based on the group's normative conventions and standards".