The idea that people make calculated decisions that allow them to obtain the most goods with the smallest amount of effort—a complex hypothesis called ‘economic man’ for short—often has been challenged. People sometimes make irrational decisions, they rarely possess sufficient information to make the best decision, and they sometimes act against their own economic self-interest, critics say. But none of these critiques is as radical as the one advanced in the Jan. 13 online issue of Proceedings of the National Academy of Sciences (PNAS). Written by an international team of researchers, it was inspired by a workshop on biological markets (transactions in which partners, typically animals, exchange commodities for their mutual benefit) held at the Lorentz Center of the University of Leiden in The Netherlands in January.
The scientists asked themselves how far biological market theory, which has been used successfully to explain cooperative behavior in many species, could be extended. Could it be used to describe, for example, the exchange of commodities between organisms without any cognitive ability, such as microbes.
They could think of instances where single-celled organisms had been shown to avoid bad trading partners, build local business ties, diversify or specialize in a particular commodity, save for a rainy day, eliminate the competition and otherwise behave in ways that seem to follow market-based principles. They concluded not only that microbes are economic actors, but also that microbial markets can be useful systems for testing questions about biological markets in general, such as the evolution of partner choice, responses to price fluctuations and the identification of market conditions that drive diversification or specialization.
They even foresee practical applications of the work. It might be possible, for example, to manipulate ‘market conditions’ in crop fields to drive nitrogen-fixing bacteria to trade more of their commodity (a biologically available form of nitrogen) with crop plants. Via Microbes buy low and sell high.