Depth of field.
Back in the day when people used manual SLR cameras, everyone knew this trick...it's called minimizing depth of field. Open up the aperture to maximum and set the shutter speed to minimum. with that done, only objects at a precise distance from the lense will be in focus. everything either closer or further will be blurry.
How to do this on an automatic digital camera? NOt for sure but my guess is to set the camera for fast action shots. fast action shots require very fast shutter speeds to prevent blurred motion. Very fast shutter speeds will necessitate a wide aperture to allow more light in to compensate for the reduced light available due to the fast shutter speed.