Past research has shown that people with prosocial orientations exercise restraint when collectively shared resources are close to being depleted, whereas people with proself orientations tend to maintain high levels of consumption. This research seeks to extend this important finding by examining whether the presence of noise in social-ecological interaction may modify the effects of social values in a commons dilemma. Participants were taking resources from a gradually declining pool. For half of the participants, the intended consumption was subject to incidental increases in consumption (negative noise). Consistent with hypotheses, noise exerted detrimental effects on cooperation when resources became scarce, yet these effects were only observed for prosocials, not for proselfs. These results indicate that noise in social-ecological interaction plays an important role in common-pool management. It tends to undermine cooperation among those who are otherwise inclined to save resources. © 2007 by the Society for Personality and Social Psychology, Inc.