A revised method for projecting two different movies to two groups of viewers without their noticing the duality

The MORI technique reported in Mori (2003) has evolved into its second generation after the appearance of a new type of video projector with two advantages over the first generation. The new MORI technique uses a pair of DLP projectors instead of the LCD type. The improved technique does not require sideways framing of the movie for presentation as required formerly. Therefore, any ready-made movie clip can be used. Second, it utilizes a pair of circular polarizing filters instead of linear polarizers. Linear polarizing filters may leak the to-be-blocked light wave when they are tilted. Circular polarizing filters are less susceptible to that weakness. The effectiveness of the revised technique has been proved by several studies carried out in two separate laboratories in which undergraduates and preschoolers participated as eyewitnesses to observe simulated criminal events presented using this technique.