(NewsNation) — A new study suggests horses are more intelligent than previously thought after being observed quickly adapting to a treat-based game with changing rules.

Researchers at Nottingham Trent University (NTU) studied 20 horses, who were first rewarded with a treat for touching a piece of card with their nose. A “stop light” was then introduced in the second stage, and the rule was changed to the reward was only given if they touched the card while the light was off.

In the third stage, scientists introduced a penalty — a 10-second timeout where the horses couldn’t play the game or receive a reward if they touched the card while the “stop” light was on.

The team observed a sudden and highly significant reduction in errors among all the horses in the study, as they began to play the game correctly, only touching the card at the right point to receive their treat.

“At first we found that horses would just keep touching the card over and over, as they probably realized they would still get a frequent reward with minimal mental effort,” said senior researcher Dr. Carrie Ijichi.

She added, “There was no cost for indiscriminate hitting. Sometimes it paid off, sometimes it didn’t. When we introduced a cost for their errors, however, they could instantly understand and play the game properly.

“Horses are not natural geniuses, they are thought of as mediocre, but this study shows they’re not average and are in fact more cognitively advanced than we give them credit for,” Ijichi said.

The research team was expecting the horses’ performance to improve when the time-out aspect was introduced, but say they were surprised by how immediate and significant the improvement was.