A study of monogamy and sociability in zebra finches provides important new research toward understanding how social interactions are regulated by the brain.
What do humans and songbirds have in common? Both species can maintain monogamous relationships while at the same time being highly social. In new research with possible implications for human behavior, scientists studying the zebra finch, a type of songbird, found that the same brain molecule, dopamine, can simultaneously promote gregariousness among males and sexual selectivity among females.
Scientists from The Graduate Center, Hunter College, The City College of New York, and two other institutions — Weill Cornell Medicine and Houston Methodist Research Institute — conducted the study, which could lead to further understanding of how social interactions generally are regulated by brain reward systems. Much of the research took place at the Hunter College Laboratory of Vocal Learning, led by Professor Ofer Tchernichovski (GC/Hunter, Biology and Psychology) and one of the study’s authors.
The study, "Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds" was published in eLife. The researchers reported that both male and female zebra finches, who in natural conditions live together in large numbers and in close proximity, responded to song (produced only by males), but in a sex-specific manner. In these experiments, it was found that they released the brain chemical, dopamine, in response to the songs in sex-specific ways as well, which could provide a mechanism of how different behaviors in each sex are reinforced. In males, dopamine supported the social function of the song. In females, dopamine activated sexual selectivity only for their mate’s song.
Postdoctoral associate Kyrill Tokarev (Hunter, Psychology), lead author of the study said that, “Actually, our first finding was very surprising: females did not seem to have elevated levels of striatal dopamine when they heard a mix of songs, but males did — while the most common interpretation of birdsong is that it is used for attraction of females by males. What we found in the second set of experiments though was that females seem to be highly selective about the songs they would find rewarding — namely the song of the mate and not other males. So, all this seemed a bit of a conundrum at first, but it brought us to an idea that song in zebra finches and other social birds can serve to maintain a dual function: gregariousness and monogamy.” The scientists wrote that these findings could “ultimately provide insights into social and sexual behavior in people.”