Biological Market examples:
Grooming in primates
vervet monkeys in the Loskop Dam Nature Reserve, South-Africa
photo: Ronald Noë
Primates trade grooming against other services, such as access to infants, tolerance at food sources and support in conflicts
Grooming is one of the few, if not the only, naturally occurring altruistic behaviour in primates that can easily be quantified. Louise Barrett and Peter Henzi were the first to systematically look at grooming from a biological market point of view. They realised that grooming can be traded, both for itself as well as for other commodities, such as tolerance near resources, access to young infants, support in conflicts and compliance during mating. Grooming thus has something in common with a currency that can be used to pay for different goods and services. The possibility of quantifying grooming opens the way to testing whether shifts in supply and demand lead to shifts in exchange rates of different commodities. The fact that grooming can be used to compensate for unbalanced trade in several other goods and services lends it a currency-like character.
(see for 'A common fallacy: reciprocity and time frames' the Biological Markets main page)
See also Dario Maestripieri's book 'Games primates play' (2012) Chpt 8 'Shopping for partners in the biological market'. This chapter gives an easy to read account of the BM paradigm with examples from primates as well as non-primates, several of which you'll find elsewhere on this site too. Oddly missing, however, is an acknowledgement of the role play by Louise Barrett and Peter Henzi in developing market ideas in primatology.
A striking example is the so-called 'baby market': the fewer infants in a group the higher the price that has to be paid in the form of grooming to gain the mother's permission to inspect and handle it. This was first described for chacma baboons, but similar results have been found in other primate species, such as sooty mangabeys and vervet monkeys (Fruteau et al. 2011), longtailed macaques (Gumert 2007), spider monkeys (Schaffner & Aureli 2005; Slater et al. 2007) and golden-snub nosed monkeys (Wei et al 2013). The latter is a highly interesting example of baby markets in a harem-species.
Negotiation over baby-grooming.mp4
The video shows how a mother holding her infant negotiates with two females that both want to touch and cuddle the infant over the length of the grooming session (captive vervet group of the Centre de Primatologie de Strasbourg)
Peter Henzi and Louise Barrett also pointed out that 'tolerance' is another important commodity that can be traded. This explains why the asymmetry in grooming between a dominant and a subordinate is strongest when resources are scarce and can be monopolized by a single animal. Rebecca Chancellor and Lynne Isbell (2008) point out that market effects also influence grooming patterns under scramble competition. Markus Port and colleagues (2009) show how important tolerance is for our understanding of grooming in primates. Their analysis reveals the effect of market forces in grooming patterns that superficially seem to adhere to the reciprocal altruism model. Barbara Tiddi and colleagues (2011) provide an important contribution to the discussion by testing the relative predictive power of dyadic reciprocity driven exchanges (as predicted by the reciprocal altruism paradigm) against partner choice driven exchanges (as predicted by the biological markets paradigm) in capuchins foraging on baited platforms. Their results confirm a number of convictions I have had for years: partner choice is much more important than partner control; tolerance is an important commodity traded on monkey markets and primate cooperation among unrelated individuals is driven by "attitudinal partner choice" (Fruteau et al 2009; the partner choice based form of de Waal's (2000) "attitudinal reciprocity"). Sick and colleagues (2014) found that grooming for tolerance in chacma baboons occurs mainly in the morning and ebbs off later in the day when bellies fill up.
The idea that sex can be traded for other commodities is much older than the biological market paradigm (see also 'Mating markets'). The idea that reproduction takes place in the context of a mating market also exists at least since Darwin set the theory of sexual selection in motion. We seem nevertheless to have inspired a few people to take a closer look at exchange rates between grooming and access to sexual partners
The popularity of this idea seems inversely correlated to the quantity of data supporting it, but here are some interesting exceptions: