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Psychologist Nick Thompson and his students study how human behaviors--like the sounds babies make--have been selected over time to support individual survival. |
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Meet the researchers:
Practicing psychology
Interview with Professor Nick Thompson, Kelly Ku and Karen Webster
Kelly Ku '03 and Karen Webster '04 recently discussed their work as part of psychologist Nick Thompson's research team. Both started their research participation at the beginning of their sophomore years, and Kelly received an Anton Fellowship to help fund her research for the academic year 2001-2003. Kelly and Karen, along with co-researchers Rachael Falcon '03, Catherine Marsh '02, Laysha Ostrow '03, and Dana Elfenbein '04, presented their research in a poster (view as html) at Academic Spree Day 2002.
Kelly and Karen, what prompted you to get involved in research?
Kelly: I was in Professor Thompson's class, a really interesting class called Human Instinct, Animal Mind (Psych 136). That was the first time I became interested in evolutionary psychology. I'd never heard about it before. I knew Clark was a school where undergrads could participate in research, so I talked to Professor Thompson. He gave me some readings on the baby cry research to see if I would be interested. To be honest, I had no idea what I was reading at that time. But I attended a few meetings of the research group and it seemed interesting, so I decided to join.
Karen: I'm one of Professor Thompson's advisees. At one point I needed him to sign my sheet of classes for the upcoming semester. He asked me what I had taken and what my grades were, and he said 'come to one of our research meetings, we're looking for people.' So I showed up, got some reading materials, and stayed. It was fun and interesting, and I was immediately put on as a member of the team, instead of being treated as an outsider, which made starting out in research a lot easier.
Nick, How did you become interested in doing research on babies' cries?
Nick: I happened to have a recording of babies crying and I played it on a tape recorder at slow speed. When you play a baby's cry at slow speed, it doesn't sound like a baby crying, it sounds like an adult crying. So immediately I began to wonder why the transformation made by a tape recorder would still make sense when you hear it. We developed an evolutionary psychological theory of why that might be the case. That was the beginning, almost a decade ago.
Can you explain what the evolutionary psychology of communication is about?
Nick: In communication, there are two interested parties, the receiver and the sender. When we talk about communication, it's as if the information is passing from one to the other. Evolutionary psychology tends to focus on how the two individuals act as selective agents on one another in the communication process. So when thinking about baby cries as a form of communication, we found ourselves asking the question, how has adult hearing selected babies' cries to be in the form that they are? And how have babies' cries selected adult hearing-the way adults respond to babies? It's the interaction between those two points of view-the natural selection of one party on the other-that makes babies' cries an interesting problem to study.
So it's a continuous feedback loop between the baby and the adult. It's not just a one-directional process.
Nick: Right.
Most of us who aren't psychologists would assume that it's the irritating nature of a baby's cry that makes us respond. We want the noise to go away.
Nick: The question is: why should babies' cries be irritating? Why should adults be constructed such that they're irritated by babies' cries? One idea is that babies and mothers have a common interest. Mothers may have been selected to be irritated by cries, because that irritation led to behaviors that served both the babies and the mothers, because they have a common interest. Another viewpoint is that the baby is manipulating the mother. Perhaps the mother does not have an entirely common interest with the child. We understand then that the baby might work on the mother in a way that is not altogether pleasant for her.
When you speak of the baby manipulating the mother, is that conscious manipulation?
Nick: No, absolutely not. The child is simply set up so that when something happens to it, it makes noises that, because of the way the mother is set up, cause her to do things.
One of the things that our particular theory highlights is that babies have been selected to make noises that constitute what we call respiratory drama. As a baby's speech apparatus matures, the baby becomes very vulnerable to choking. This fact might have led to adults being selected for paying close attention to the breathing of their infants. And this has led babies to be able to get attention and manipulate their parents using faked choking and gasping noises.
In our later work, we've been broadening the notion of what respiratory drama means. We're interested in noises that sound like interference with breathing. Think of what happens if a baby gets the bottle pulled out of its mouth, or some shock happens. The baby gives a yelp, there's a long pause with a long intake of breath, and then the baby lets out a terrific yell. The first question you ask is-and I remember this from when my kids were little-is the baby breathing? You're led to go find out what's happening.
How do you study babies' cries? How do you get participants?
Nick: We don't induce babies to cry. There are several medical settings where babies are routinely induced to cry. We've been able to use what other researchers have recorded. Our participants are college undergraduates who listen to babies' cries. Karen and Kelly were in charge of this.
Karen and Kelly, tell me what you did.
Karen: We recruited student volunteers from psychology classes. The experiment was done in two phases. When a participant came in, we would play all of the baby cry samples so that he or she could get acquainted with differences in pitch and other variables in the cries. Then we played different pairs of cries and asked the participants to rank them on a scale of similarity from 0 to 100, with 100 being identical. Then we asked the participants how they judged similarities. What variables did they use to make those judgments? This formed our list of about 16 variables for the second phase.
Kelly: In evolutionary psychology, we believe behaviors are not random, therefore we believe that crying behaviors of babies are not random, but are evolved and selected. Cries have specific patterns or features that adults are selected to respond to. Adults have to be able to tune into these features, otherwise the crying behavior of babies would serve no purpose at all. It's very important for us not to tell the volunteers what to look for. They tell us what features of the cries they think are important. We make lists of the variables that the volunteers suggest, and count up the ones that are given most frequently.
Karen: When the volunteers come back for the second phase, we play all the cry segments again to re-familiarize them, and give them a response sheet for each cry. The volunteers rated each cry for each variable on a scale: for example, not urgent to urgent, or not whiny to very whiny. After that, we ask a few questions such as
- in what circumstances do you think that the baby is crying?
- what do you think the baby is feeling?
- what is your emotional response to this cry?
Then, using special computer audio software, we did our own measurements of the physical variables of the cries, to co-relate the perceived features of the participants and the actual physical variables of the cries.
Kelly and Karen, can you talk about the advantages and disadvantages about being involved in research as an undergraduate?
Kelly: At least in this research, there's a lot of work. We spend at least ten hours each week. It's also a complicated theory.
Karen: And the work is sometimes tedious. It's not easy.
Nick: It's a very intricate research protocol as well, and only they know how to do it. I'm scared to let them go home for vacation!
Kelly: But once you get involved in it...First of all, it helped me learn about my abilities. I never thought I'd know how to use things like statistics and audio software. It's really hard to learn in the beginning, but once you've gotten to know how to use them, it's really an advantage to you as a student and in your future career. And we have a really great group.
So you have a sense of camaraderie?
Karen: We do. If you sit in on one of our meetings, that shows. It's entertaining. We're always in the same room together, because we're always working on this. We're always on the phone or emailing each other about something. We're definitely in contact with each other, instead of doing our own little thing and not checking in with the rest of the group.
How is doing research different from taking a class?
Kelly: It's so different. Traditional class is more like a lecture--the student listens, occasionally you ask a question. There's not so much interaction going on between professor and student. With a research group you get to raise your own ideas, and you make the decision with the professor. It's not like Professor Thompson tells us what to do, but we tell him what we want to do and he gives us his opinion. and then we rethink that. It makes you a lot more independent, because you know you can't totally rely on your professor. You have to come to your own decisions.
Karen: And if something's not working, we have the power and authority to say, this is not working and we're changing gears. And the professor says, okay, you're the ones doing the project, you know better than I. Now what are we doing?
So you're actually becoming practicing psychologists.
Karen: Exactly.
Nick: Absolutely. Essentially, somewhere between the ages of 18 and 40, most people make a transition from being good children to being effective adults. That transition can be made really late or it can be made really early. Many kids graduate from college without having made that transition. I like to see them do it in the sophomore year and I like to see them do it for my own very selfish reasons. Because if they can make that transition within my laboratory, then I have a good, creative, effective working group. And we actually get new stuff done. It's really important to be one of the students who makes that transition early. I think that maybe the 40-50% of our majors who get involved in research are ready to go out into the world and do something, and I'm really pleased about that aspect of our program.
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Additional Resources
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The idea for the experiment came from conversations between Rachael Falcon '03 and 
Kelly uses audio software to examine the 
Explore a 
Kelly Ku '03
Karen Webster '04
Professor Nick Thompson
Finding a research question.