A new study by researchers at Duke University finds that a little extra stress and stimulation makes hyper dogs crack under pressure, but gives mellow dogs an edge, Futurity reported.

The Duke team consists of Emily Bray and evolutionary anthropologists Evan MacLean and Brian Hare of Duke's Canine Cognition Center, who conducted an experiment with the dogs to find out how their actions will be affected by underlying temperament.

The idea in psychology called the Yerkes-Dodson law says that a little stress can be a good thing, but only up to a point. When the pressure is too much, the performance will be affected but for tasks that are less challenging, it would be hard to stay engaged.

"The relationship between stress and performance follows a Goldilocks model: Both people and animals function best when the level of stress is not too much, nor too little, but just right," Duke Today reported.

"When you're taking a test, for example, it helps to be a little bit anxious so you don't just blow it off," said study co-author Bray. "But if you're too nervous, even if you study and you really know the material, you aren't going to perform at your best."

Thirty pet dogs were tested ranging in age from an eight-month-old Jack Russell terrier named Enzo to an 11-year-old Vizsla named Sienna. Aside from that, 76 assistance dogs from the Canine Companions for Independence in Santa Rosa, California were also tested.

The reaction of the dogs were based on the number of tail wags. It was found out that naturally calm and laid-back dogs get a boost in their ability while with excitable dogs the pattern was reversed.

A video shows a high-arousal trial where a two-year-old spaniel named Charlie Brown loses focuses when under pressure.

The results of the research will help develop better tests like in determining which dogs are likely to graduate from service dog training programs.