Brains Designed For Cooperation

diagram showing cooperative bird song
Plain-tailed wrens cooperate to sing a synchronized duet.
Zina Deretsky, National Science Foundation

The music starts. You take your lover in your arms. Your bodies begin to sway in time to the music. It all seems so natural. And it is. Without your conscious thought, billions of neurons in your brain are acting and reacting to your lover’s movements. At the same time, your lover’s brain is doing the same thing. The result is a graceful symphony of motion.

Our brains were designed for cooperative activity, whether it’s dancing (or doing anything else) with our lover, working in a crowded office, or constructing a house with workmates. Eric Fortune, behavioral neuroscientist at Johns Hopkins University, studied the process and reported on it in the November 4 issue of the journal Science.

Fortune, of the Department of Psychological and Brain Sciences at the Krieger School of Arts and Sciences, explains, “What we learned is that when it comes to the brain and cooperation, the whole is definitely greater than the sum of its parts. We found that the brain of each individual participant prefers the combined activity over his or her own part.”

The study not only helps us to understand ourselves as social creatures, but it provides guidance for engineers programming autonomous robots that cooperate with other systems in settings such as bomb squads, construction, and combat. (Think Skynet’s Terminators.)

Fortunately, Fortune’s work didn’t require facing down killer androids on a wreckage-strewn battlefield. Instead, he and his team took to the cloud forests of Ecuador, on the slopes of the active Antisana Volcano. Here, he found lovers in action; plain-tailed wrens, chubby-breasted rust-and-gray birds who hop and flit through the area’s bamboo thickets, and who are famous for their synchronized duets. Their songs — sung by one male and one female — take an ABCD form, with the male singing the A and C phrases and the female singing B and D.

“What’s happening is that the male and female are alternating syllables, though it often sounds like one bird singing alone, very sharply, shrilly and loudly,” explained Fortune, who spent hours hacking through the thick bamboo with a machete, trying to catch the songbirds in nets. “The wrens made an ideal subject to study cooperation because we were easily able to tape-record their singing and then make detailed measurements of the timing and sequences of syllables, and of errors and variability in singing performances.”

The team then captured some of the wrens and monitored activity in the area of their brains that control singing. They expected to find that the brain responded most to the animal’s own singing voice. But they got a surprise.

“In both males and females, we found that neurons reacted more strongly to the duet song – with both the male and female birds singing – over singing their own parts alone. In fact, the brain’s responses to duet songs were stronger than were responses to any other sound,” he said. “It looked like the brains of wrens are wired to cooperate.”

So it’s clear that the brains of plain-tailed wrens in the Andes of Ecuador have been designed to work cooperatively, and to prefer “team” activities to solo ones. But what does that have to do with us?

“Brains among vertebrate animals – frogs, cats, fish, bears and even humans — are more similar than most people realize,” Fortune said. “The neurotransmitter systems that control brain activity at the molecular level are nearly identical among all vertebrates and the layout of the brain structures is the same. Thus, the kinds of phenomena that we have described in these wrens is very relevant to the brains of most, if not all, vertebrate species, including us humans.”

So the next time you’re dancing — or doing something else — with your lover, remember that your brains were designed for this team activity.