Numerous renewable resources have been exploited beyond limits for sustainable economic development. At times over-exploitation has been observed even in cases where management regimes have been in place. Thus it seems pertinent to search for explanations beyond the theory of the commons. An experiment is performed where subjects set reindeer quotas in a district where lichen has been severely depleted by preceding overgrazing. All subjects err on the side of over-exploitation. Behaviour seems to be dominated by inappropriate, static mental and inefficient heuristics. Hence a subtle information problem is revealed.