UAA student tickles rats for research

Although we can't hear it with the naked ear, rats can, and do, laugh. Scientists say there’s a lot to be learned from it.
Published: May. 2, 2021 at 6:50 PM AKDT
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ANCHORAGE, Alaska (KTUU) - Laughter has always been somewhat of a mystery. There’s little information on why humans do it, but we know we’re not the only ones who do. In fact, rats can and do laugh, and scientists say there’s a lot to be learned from it. It’s the center of a research effort by a group of students and teachers at UAA.

UAA psychology senior Tucker Sawyer is researching rat laughter for his senior thesis. He’s working to identify and categorize these ultrasonic vocalizations. Now Mother Nature isn’t exactly rich with one liners, so how exactly do you make a rat laugh? Well, you tickle them!

“Understanding the phenomenon of rat laughter can benefit animal welfare as well,” said Sawyer. “Being able to use different tactics to cause ultrasonic vocalizations of laughter can create a positive effect in these rats that makes them not only comfortable with humans but could potentially make them perform better on tasks related to human interaction.”

The ultrasonic vocalizations can’t be heard by humans with the naked ear, so they use special software to slow down the frequencies to better study them. Associate Professor of Psychology Dr. Gwen Lupfer says it could eventually lead to an understanding of the origins of our own sense of joy or even the way we interpret drug research.

“They experience withdrawal just like people do,” said Lupfer. “One indicator of how much they’re enjoying the drug use are these vocalizations. They make happy sounds when they get high and they make less happy sounds when they are experiencing withdrawal. So recording these laughs can and is being used by researchers for work that probably can and will generalize to people and help people.”

It’s a species not often embraced by humans, but if you take a closer listen, you’ll find we’re not so different after all.

“I love this line of research because it’s unbelievably humane,” said Lupfer. “You don’t have to do anything they dislike at all. You literally just play with them, and get really interesting data which I love because most researchers who work with rats at some point fall in love with them.”

Humans can hear sound wave frequencies up to 20 kilohertz and rats laugh at around 50 kilohertz. Research suggests they laugh at such a high frequency to protect them from predators.

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