Serotonin and a Buyer's Market

In the current housing market, a seller's serotonin levels may determine just how likely a buyer's low offer will be accepted. Serotonin depletion and the acceptance of unfair offers were recently explored on a smaller scale by researchers at the University of Cambridge and UCLA by using the so-called Ultimatum Game—a game which uncomfortably resembles today's property transactions.

The investigators examined the responses of 20 healthy volunteers, who underwent a double-blind, placebo-controlled depletion of tryptophan,* the amino-acid precursor of serotonin. After the procedure, participants were offered 1 of 3 ways to split a sum of money with another player: fair (45% of stake); unfair (30%); or most unfair (20%).

The investigators found that respondents were significantly more likely to reject "most unfair" offers after tryptophan depletion than after placebo treatment (F = 7.551; P = .013). However, the rejection rates of fair or unfair offers were not significantly affected by tryptophan depletion. On the basis of related assessments, the researchers concluded that the higher rejection of "most unfair" offers with tryptophan depletion could not be attributed to other factors, like changes in mood.

* Acute (5-hour) tryptophan depletion results from the ingestion of a tryptophan-free amino-acid drink (see Young SN et al. Psychopharmacology (Berl). 1985;87:173-177).

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