Finally, it may not be rational for an individual to participate

in group activities which will benefit him. Indeed, if he can avoid the

cost and obligations of group activities but share in the benefits with-

out undermining group functioning, he obviously is rational.

 Whether and how these problems can be overcome depends on the

character of the group in question. Some successful group activities are

based on the indigenous voluntary groups which exist in rural societies --

kinship, religion, labor exchange, credit associations, etc. Size is im-

portant; particularly if the group is small enough so that each individual's

actions perceptibly influence the group's fortunes, the internal social

pressures for cohesive action can be strong.2 But the group needs to be large

enough to generate economics of scale. Perhaps the optimal size for such

voluntary interaction is around 30 35 people -- the size of the Chinese

work team,3 of successful midwestern food cooperatives,4 or of groups in

Mexico's Puebla Project.5

 These social pressures were utilized at Comilla, where the credit
associations were required to have weekly meetings to maximize the face-


 Mancur Olson, The Logic.

 2Mancur Olson, The Logic..., pp. 53-57.

 Carl Riskin, "Maoism and Motivation: Work Incentives in China,"
in Victor Nee and James Peck, eds., China Uninterrupted Revolutions From
1840-to the Present (New York: Pantheon, 1973), p. 431.

 Ron Cotterill, The Social Economics of Participatory Consumer
Cooperatives (East Lansing: Michigan Sate University, Department of
Agricultural Economics, Agricultural Economics Report No. 369, December 1979),
p. 31.
 5Allen Jedlicka, Organization for Rural Development, p. 74