New Issue: Orbital Catastrophe Ahead? Read Now

Is That Your Final Offer?

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Serotonin, a chemical that in the brain affects mood, also seems to control behavioral reactions to unfairness. Researchers at the University of Cambridge depleted the serotonin levels of volunteers in part by feeding them a cocktail of amino acids that lacked tryptophan, an ingredient that the body needs to make serotonin. The volunteers then played an ultimatum game, in which they had to decide whether to accept an offer by a “proposer” to split, however unevenly, a pot of money. Rejection of the offer meant that no one got anything. Lack of serotonin, the experimenters found, made refusal more likely—for instance, 82 percent of serotonin-deprived individuals refused a 20 percent piece of the pie, compared with 67 percent of normal subjects given the same ultimatum. Take it or leave it from the study published online June 5 by Science.

Philip Yam is the managing editor of ScientificAmerican.com, responsible for the overall news content online. He began working at the magazine in 1989, first as a copyeditor and then as a features editor specializing in physics. He is the author of The Pathological Protein: Mad Cow, Chronic Wasting and Other Prion Diseases.

More by Philip Yam
Scientific American Magazine Vol 299 Issue 2This article was published with the title “Is That Your Final Offer?” in Scientific American Magazine Vol. 299 No. 2 (), p. 36
doi:10.1038/scientificamerican0808-36b

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe