 It has been widely held, for instance, that the conditions under which group selection can effect evolutionary change are quite stringent and rare. Typically, group selection was seen to require small group size, low migration rate, and extinction of entire  demes.[3]  Some modelers, however, disagree that these stringent conditions are necessary, and show that in the evolution of altruism by group selection, very small groups may not be necessary (Matessi &amp; Jayakar 1976: 384; contra Maynard Smith 1964). Others also argue that small effective deme size is not a necessary prerequisite to the operation of group selection (Wade &amp; McCauley 1980: 811). Similarly, another shows that strong extinction pressure on demes is not necessary (Boorman 1978: 1909). And finally, there was an early group selection model that violates all three of the “necessary” conditions usually cited (Uyenoyama 1979; see Wade 2016).