A COMPARISON IS MADE BETWEEN THE TEACHING MACHINE AND HORIZONTAL AND VERTICAL TEXT FORMATS. A TEACHING MACHINE PRESENTS AN ORDERED SEQUENCE OF INSTRUCTION TO THE LEARNER, ONE FRAME AT A TIME. AFTER RESPONDING TO A STIMULUS FRAME, THE LEARNER'S ANSWER IS IMMEDIATELY CONFIRMED OR CORRECTED. THE LEARNER PROCEEDS TO THE NEXT FRAME AND IS PREVENTED FROM CHANGING HIS PREVIOUS ANSWERS OR GOING BACK IN THE PROGRAM. IN A HORIZONTAL PROGRAMED TEXT, SUCCEEDING FRAMES APPEAR ON ALTERNATE PAGES. ANSWERS ARE WRITTEN EITHER IN THE BOOKLET OR ON SEPERATE ANSWER SHEETS. BY TURNING THE PAGE, THE LEARNER RECEIVES THE CORRECT RESPONSE WITH THE NEXT STIMULUS FRAME. MUCH PAGE TURNING IS REQUIRED. VERTICAL PROGRAMED TEXTS ARE READ FROM THE TOP OF THE PAGE TO THE BOTTOM. A MASK OR SLIDER IS USED. THE LEARNER EXPOSES ONE FRAME AT A TIME, TOGETHER WITH THE ANSWER TO THE PRECEDING FRAME, BY MOVING THE SLIDER DOWN THE PAGE. AS EACH NEW FRAME IS EXPOSED, THE LEARNER WRITES HIS ANSWER EITHER IN THE BOOK OR ON A SEPERATE ANSWER SHEET. LITTLE PAGE TURNING IS REQUIRED. SEVENTY-SEVEN 8TH GRADERS FROM HANOVER, N.H., WITH IQ'S RANGING FROM 73-142 (118 MEAN) WERE ASSIGNED TO DIFFERENT MODES OF PRESENTATION. THE 65-FRAME PROGRAM USED WAS DESIGNED TO TEACH THE DIFFERENCE BETWEEN NUMBERS AND NUMERALS. IT WAS FOUND THAT INTERMODE DIFFERENCES IN LEARNING WERE NOT STATISTICALLY SIGNIFICANT. SUBJECTS USING THE PROGRAMED TEXTS COMPLETED THE PROGRAM IN LESS TIME THAN DID SUBJECTS WHO USED THE MACHINES. IT WAS RECOMMENDED THAT THE INTERACTION BETWEEN IQ AND PRESENTATION MODE BE STUDIED MORE CLOSELY AND THAT, EXCEPT FOR PROGRAMS CONSISTING MAINLY OF COPYING FRAMES, THE VERTICAL-PROGRAMED TEXT FORMAT BE USED.