  Evolutionary games are studied where the teaching activity of players can
evolve in time. Initially all players following either the cooperative or
defecting strategy are distributed on a square lattice. The rate of strategy
adoption is determined by the payoff difference and a teaching activity
characterizing the donor's capability to enforce its strategy on the opponent.
Each successful strategy adoption process is accompanied with an increase in
the donor's teaching activity. By applying an optimum value of the increment
this simple mechanism spontaneously creates relevant inhomogeneities in the
teaching activities that support the maintenance of cooperation for both the
prisoner's dilemma and the snowdrift game.
