By Charlotte Rosenfield ’15, Design Editor
By Charlotte Rosenfield ’15 Design Editor
Melissa Coleman is an assistant professor in the Keck Science Department. Coleman, with her colleague Eric Fortune, recently published an influential study the popular journal Science. I sat down with her on Friday, Nov. 4.
Charlotte Rosenfield: First of all, could you let our readers know what the study you’ve just gotten published is about?
Melissa Coleman: What we were interested in was how two organisms cooperate to produce a coordinated behavior. One example we give of this—which I think is a really good one—is two people dancing, for example, the tango. For two people to produce this dance, the sum of the whole is more than its parts. If you have one person who dances her part and another who dances his part, when they come together; those motions change because each person is getting feedback from his or her partner. With cooperative behavior, even though you know your part, your movement and behavior will change based on what your partner is doing.
CR: How did you and Eric study this type of interaction?
MC: We studied both the internal and the external activity of Plain-Tailed Wrens. First we were studying the behavior in these birds and how they coordinate their songs. And then secondly, we wanted to see how the nervous system enables this coordination. No one [before us] had looked into the nervous system and discovered how it is able to produce these coordinated activities. So we heard about this bird that produced this song, before the event actually occurs and it’s quite remarkable. If you listen to their song, it sounds like one bird singing it. It’s very, very precise. It’s really fast, so the nervous system has to get on line moment- to-moment.
The first thing we were able to do was figure out which bird was singing which part. Sometimes they sing by them- selves—like they’re practicing—and we found that it’s usually the females that do this. We took this as an indication that the females are the ones leading the song. We don’t have conclusive evidence, but everything is consistent with this [conclusion]. What also suggests that the female wrens lead the interaction is that sometimes they’ll be singing a duet and just the male will drop out—almost like he made a mistake or lost interest—but the female keeps going. And so we think, behaviorally, the female is leading the song.
What we really wanted to know was how the nervous system can produce this coordinated behavior. [Like I said], nobody has ever been able to track this before. So we went to Ecuador and recorded the songs of birds in their habitat. We set up a lab, out in the middle of the jungle, so that we could look at their brain activity. It took a long time, but we were finally able to capture these birds and anesthetize them so we could look to see what their brains were doing. What we found—something that, in hindsight, seems a bit obvious—was actually quite surprising at the time: the brain prefers the song of the duet to the summed response of the male and female parts of the song. The response of the brain—how many action potentials the neurons fire, or how active everything is—is greatest in duets, greater than in either the male or female parts combined. So we’re proposing, based on our findings, that the brain has actually evolved to produce coordinated behaviors; that we are wired to cooperation.
[Returning to the tango metaphor,] it’s not like you’re saying, “Oh, I know my part.” It’s not like I have a memory of my part in my head and the male has the memory of the male part in his head. Instead, the memories that we have are wired best toward a duet, rather than toward recognizing our parts individually.
CR: So do your findings also apply directly to humans?
MC: We think so. And the other application we hope it has is to robotics. As people are trying to figure out how humans are going to interact with robots, we’re realizing that you can’t just program the robots to do a specific act; their interactions have to depend on feedback [from a person or another robot] to have a certain response.
CR: How did you arrive at this type of research? Was it the birds themselves? Was it the nervous system?
MC: My general, overall interest is how the nervous system produces behaviors. As a graduate student, I looked at rhythmic behaviors—things like walking and breathing, which have a pattern to them. And then I studied how birds produce and learn their song. Typically, birds have to learn their songs from their parents, and there are actually very few species that learn their vocalization. These include dolphins and whales, some bats and some hummingbirds. Cats and dogs vocalize, but nothing’s learned. We learn our speech from our parents; you’ve probably heard horror stories about people who were isolated and never learned proper speech patterns. Birds are exactly the same way [when it comes to song acquisition as we are when it comes to language acquisition]. Both birds and humans require hearing and a tutor, making an internal memory of the sound and then matching their vocalization to the memory.
If you’re interested in how the nervous system produces learned vocal communication, birds are an obvious place to go look. I also have birds—finches—here in my lab. We look at how birds learn their songs, and some of my students are looking at how the nervous system is built to recognize songs. [My students are working on investigating] how you can change that [recognition, and how it’s wired within the brain].
What initially piqued my interest in the study with the wrens is that we would be able to separate the motor output—the actual singing itself—from the sensory hearing. With the tango, it’s obvious [how to separate the two] because you have to get feedback from your own body, about where your body is in space, but you also have to get feedback from your partner. The sensory and motor portions are hard to separate in the finches we study [here in Claremont]. But with the wrens [Eric and I studied] they’re easier to separate because you have these two parts of the song.
CR: Were you always interested in science?
MC: I’ve always been interested in biology, and in science [more generally]. That never really changed. At one point I thought that I might want to be a vet, but then I realized that that wasn’t really for me. So I went into research. Teaching was something I became interested in in addition to research. When I was looking for jobs, I was looking for something where I could do some teaching and some research. I didn’t want to be
CR: What are some of the courses that you currently teach? MC: Right now I teach almost exclusively neuroscience classes. I teach in the “Foundations of Neuroscience” class, which usually has fairly large enrollments. That’s a great class since we have teachers from Scripps, Keck and Pitzer coming together. We teach everything from cell-molecular biology to philosophy.
I also teach two of the upper-level, foundational neuroscience classes. [In these classes] we go over how neurons work in great detail: how the nervous system works, how your eyes work, how you ears work, that kind of thing.
[In addition to those three classes on neu- roscience], I teach a seminar class where we just read papers, which is fun. I teach in a class for non-science majors about cool things that animals do and how the nervous system enables those things to happen. For example, bats echolocate to catch their prey; we look at how the nervous system enables that.
CR: How do you promote a good student- teacher relationship in workspaces like labs?
MC: Well, here it’s easy because everyone wants to do research. So I’ve got a lab full of students, and they’ve been very successful.
It’s fun to have students come into lab and see what it’s like and say, “Oh yeah, this is pretty cool.” I really enjoy that part. I’ve had some really great students who have gone on to do some amazing things.
CR: Have you taught at other institutions?
MC: I haven’t, actually. I went straight from doing research, as a post-doctoral fellow, to being a teacher here.
CR: What is your general teaching philosophy?
MC: I like for students to know where ideas come from. So I won’t just say, “Here’s what we know. Memorize it and spit it back out.” There’s no point in that. My goal, and I don’t know if I achieve this, but what I try to do is give students a sense of what the field is like. When they leave my class and go on and read literature, or become medical doctors or researchers in the field, I want students to have this base that they can draw from. I hope I give a good introduction to the field. I also want to give people an idea of how to do science. I want to give them a sense that it’s a little harder to do than just going in and doing whatever experiment they feel like doing. There’s more to it than that.
I teach two classes that are designed to be accessible for non-science-majors. I want them to enjoy the science. I’ve had some people come in and say, “I had science in high school. I hated it. I’m just here because I have to take it.” So first of all I try to erase the “I hate science” part by making it fun and interesting. And then I try to show students a little bit of the methods going on and give them an idea about how to actually do science.
CR: How would you say your study that got published in Science compares to some of your other achievements? Are you striving for more?
MC: Oh, you still strive for more. You always strive for more.
CR: Do you want to do more with this study, or are you finished with it?
MC: Well, we’re still going to follow this up. This was just a few months that we went down there and collected this data. [It was by no means an exhaustive study.] The next thing we want to do—aside from more fully characterizing the behavior of the wrens—is to look at how the brain is behaving while they are singing to each other.
Hopefully next year I’ll be on sabbatical and will be able to go visit some friends’ labs. That should help me set up better technological techniques to try and answer some of the lingering questions.