Rats are really good at hide-and-seek — and they get a kick out of it: study

Transcript

Not only can rats play hide-and-seek, but they jump and squeal for joy when they win. 

This is according to a study by scientists at Berlin's Humboldt University published last week in journal Science.

"We were really surprised how well they can do it," neuroscientist Annika Reinhold, the study's co-author, told As It Happens host Carol Off. 

"Especially the strategies that made it clear that they are really capable of some really complex cognitive tasks."

'They are actually very good in this game'

Scientists have long known that rats are very smart. They can solve puzzles and run through mazes. And both wild and domesticated rats have been known to engage in play.

Reinhold and her colleagues wanted to know just how far that play can go, so they took six rats to a basement and set up various hiding places around the room in the form of boxes and barriers. 

First, they spent some time getting the rats used to the team and the play area. Then they played a modified version of hide-and-seek with the rodents, teaching them first how to hide from the researchers, and then to seek out the hiding scientists.

"We weren't sure if they can do it as good as we wanted them to play it. But we were really surprised that they are actually very good in this game," she said.

"So they can play both hide and seek, and they can switch between the roles — which is kind of the most impressive cognitive parts of the game. ... They also use both roles and play them in a strategic way." 

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It took the critters an average of three weeks to master the rules of the game, Reinhold said, and they became quite clever at it, shunning the clear hiding spots for opaque ones. 

"What it shows to us is that they really kind of understand the game and the reason for hiding," she said.

No snacks — just snuggles

When the rats were successful in either hiding or seeking, the researchers would reward them with physical attention like "hand-chasing, stroking, patting [or] tickling."

"We didn't want them to play that game for food reward because that would basically disturb the playful role of the game," Reinhold said. "So we wouldn't know if they would play it just for eating, or because they actually had fun."

And it appears they did, indeed, have fun.

Not only did they they exhibit neural activity that indicated a positive experience, but they would squeal and jump excitedly whenever they won.

In fact, they appeared to be having such a good time that they tried to make the games last longer — delaying their gratification. 

"They were also prolonging the time by running away or re-hiding, so that it would take them longer until they would get tickled," Reinhold said. 

Written by Sheena Goodyear. Interview produced by Kate Cornick and Marc Apollonio.