 Figure 17: Evolution toward Nowak and Sigmund’s “Generous Tit for Tat” in a world of imperfect information (Nowak &amp; Sigmund 1992). Population proportions are shown vertically for labelled strategies shown over 12,000 generations for an initial pool of 121 stochastic strategies \(\langle c,d\rangle\) at .1 intervals, full value of 0 and 1 replaced with 0.01 and 0.99 (Grim, Mar, &amp; St. Denis 1998). [An  extended description of figure 17  is in the supplement.]