Stress ‘sweet spot’ differs for mellow vs. hyper dogs. Duke Today, July 21, 2015. People aren’t the only ones who perform better on tests or athletic events when they are just a little bit nervous — dogs do too. But in dogs as in people, the right amount of stress depends on disposition. 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. Picked up by the Daily Mail, the News & Observer and CBS News.