Some consumer and environmental movements have flourished in rich countries, even though Olson's theory suggests that firms and polluters should have a strong organisational advantage over consumers and inhalers of dirty air.
She managed to find just over 40% of the original study group, and set about working out why some had stayed poor while others had flourished, and whether the favelas were the poverty traps that they seemed to be.
Because new technology has flourished since then, scientists could discover that some new systems are also at risk, said Jeffrey Hughes, director of the Center for Integrated Space Weather Modeling at Boston University.