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UW Research Highlight: Why we need to hear each other

March 13, 2012

The next lasers in science fiction post will be coming soon, but I’m pushing it back a bit – I’ve been focusing most of my science-writing energy elsewhere this week.

As some of you know, I’ve recently joined the science staff at the Daily Cardinal, one of UW-Madison’s two daily student newspapers. Last week, I interviewed Leslie Seltzer, a postdoctoral fellow at the Child Emotion Research Lab in the psychology department, for a short research highlight that was published in today’s paper.

Leslie does some fascinating research, and I really enjoyed getting to interview her. She studies the evolution of language, and has recently done some cool experiments showing that we react differently to speech than we do to written language.

In the experiment I wrote about in this research highlight, for example, she put a group of young (~10 years old) girls through a stressful situation, and then monitored the changes in their stress levels as they interacted with their mothers either in person, on the phone, or by instant message.

I’ll let you read the article for Leslie’s conclusions and the details on the study. However, I wanted to highlight a few things here that I thought were interesting but that didn’t make it into my final version of the story.

What cortisol and oxytocin do in your body

One of the things that I didn’t really get to go into in this story, for example, was the roles of oxytocin and cortisol in the body. In the story for the Daily Cardinal, I wrote that “cortisol is released in response to continuing stressful situations” and “oxytocin is involved in female reproductive processes but also plays a role in forming and maintaining social relationships.”

These short descriptions were fine for explaining Leslie’s research, because all you need to know is that she measures cortisol to monitor the girls’ stress levels, and she monitors oxytocin to look at attachment, trust, and comfort. However, these short explanations only scratch the surface of some really interesting stuff going on in our bodies.

Cortisol, for example, is a steroid hormone, which is produced in the adrenal gland in your brain as part of a system that helps you react and adapt to your environment (this system is called the HPA axis – there’s a nice quick explanation here and a more technical one here). The term “steroid” just refers to cortisol’s molecular structure, which contains several rings of atoms fused together and is similar to the structures of things like cholesterol and testosterone.

As she explained cortisol’s role in the body, Leslie returned several times to an analogy about the response you might have if you run into a bear in the woods. She explained that when you first turn around and see a bear staring at you hungrily, your immediate startled response is caused by neurotransmitters released in your brain. This instant “stressed” response is NOT caused by cortisol.

However, if you start running and the bear starts chasing you, and you keep getting stressed out during the chase, then cortisol starts to kick in. As your cortisol levels go up, your body puts less energy toward non-essential processes and more toward keeping you alive. As Leslie put it, your physical response to cortisol is that it puts you into “hyper self-preservation mode.”

Running into a bear is a little more extreme than most situations we face in everyday life, but your body does release cortisol in other ongoing stressful situations. So, measuring cortisol was a useful way to measure changes in the girls’ stress levels after the math and verbal exam that Leslie put them through in her study.

Oxytocin, on the other hand, has a very different structure than cortisol and plays a different role in the body. It is a peptide, or a short protein, consisting of nine amino-acid building blocks. Scientists have known for about a century that oxytocin is essential to female reproductive processes, like helping the uterus to contract during birth and helping a mother’s breasts release milk.

However, about 30 or 35 years ago, scientists started to realize that oxytocin (or its closely related variants) shows up in a lot of species that don’t need it for reproductive purposes. This suggested that it has other important functions as well.

And sure enough, recent research has shown that oxytocin mediates a lot of social interactions. It’s involved in mother-infant bonding and in other relationships, like friendship and sexual relationships between adults. It also plays a role in helping recognizing individuals that you’ve seen before (see for example here,  here and here).

Okay, enough about hormones and biochemistry.  What other stuff did I learn while I wrote this story?

Speech is a lot older than writing.  And I mean A LOT.

One of the other interesting things I learned when I wrote this story is that speech, or other forms of vocal communication, are a lot older than writing.  And by a lot, I mean A LOT.  In Leslie’s article on the text vs. speech experiment, for example, she points out that “vocal signalling” (which was the predecessor to speech) dates back hundreds of millions of years, while writing is relatively recent (think five or six thousand years).

In retrospect it’s kind of obvious that spoken language had to precede written language, but I’ve never really thought about the timescales involved.  I was particularly surprised to hear that written language is as “young” as it is!  At any rate, I thought this was pretty cool, but it didn’t really have a place in the article I wrote.

Undergrads get to do some awesome stuff in research labs on campus

The stuff about cortisol and oxytocin and the history of written language was mostly “extra” information, so while it would have been fun to include it, I didn’t feel too bad leaving it out. The one thing that I’m a little sad I didn’t manage to highlight in this story, though, is that the second author on the paper was an undergraduate.

I just thought I’d mention this, because there are a lot of undergraduate researchers doing serious research on campus, and the more I hear about their work, the more impressed I am. I’d like to highlight their accomplishments when I can; unfortunately, it just didn’t fit into this story. However, Leslie told me that Ashley was really involved with helping design and run the experiment, and I think that’s awesome.

So, anyway, you can find the article here if you haven’t already read it. Hope you enjoy it, and let me know what you think!

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For those of you who are interested in reading the original research articles, the links are below. Unfortunately, these journals aren’t open-access, but these links should at least be useful if you’re on a campus with academic journal subscriptions:

  • Leslie’s first study, showing that hearing mom’s voice over the phone helped girls de-stress almost as much as interacting in person (i.e. you don’t need physical contact)
  • Leslie’s second study, showing that reading comforting words by instant message was not as effective as talking in person or over the phone, suggesting that there’s something important about human speech beyond just the words and grammar in the language
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