sentences:  Sloboda (1974, 1977) cleverly applied Levin & Kaplin's (1970) 'light-out' method in an experiment designed to measure the size of the span in music reading.Sloboda (1977) asked his participants to sight read a melody and turned the lights out at an unpredictable point during each reading.The participants were instructed to continue playing correctly 'without guessing' for as long as they could after visual input was effectively removed, giving an indication as to how far ahead of their hands they were perceiving at that moment.