Traditional instruction in reading is grounded in a bottom-up model which asserts that learning occurs from part to whole. Thomas C. O'Brien (1989) suggests that this model was fueled by the industrial revolution in America. Educators developed an assembly line mentality, which assumed that readers are built like cars —part by part. If all the parts which go into a car are assembled correctly and in the prescribed order, then the final product should run well.
Kirk, C. A. (1994). Meaningful Reading: Instruction for Children Experiencing Reading Difficulty. Reading Horizons, 34 (4). Retrieved from https://scholarworks.wmich.edu/reading_horizons/vol34/iss4/4