1. Left-handed athletes have been shown to have an advantage in interactive sports such as tennis, with left-handers making up a disproportionately high percentage of top players. 2. One theory for this advantage is the "negative perceptual frequency effects" hypothesis, which suggests that right-handed athletes are less practiced at perceiving and predicting movements from left-handed opponents. 3. A study tested this by having right and left-handed participants with different levels of tennis experience try to predict the direction and depth of tennis shots from video clips of both right and left-handed players. It found support for the idea that the ability to perceive left-handed movements is less developed.