This paper presents a mechanism to cooperation in large scale resource social dilemmas. The mechanism was developed considering the Colombian electricity crisis (1992-1993). The paper offers a dynamic hypothesis as extension of the small scale resource social dilemmas theory to large scale situations that integrates the effects of delays, expectations, and perceptions about cooperation. This work also presents simulations that suposes the dynamic hypothesis as explanation of the variation of the electricity demand in the 1992 1993 Colombian electricity crisis. The results explain also the variation of demand after and before shortages in that crisis. As a conclusion, we suggest that perception, and expectations in dynamic complexity situations should be considered as a fundamental issue for explaining cooperation.