Final answer:
Frederick Taylor developed the pay principle of differential piece-rate system based on his scientific management theory. This principle involved paying workers different rates per unit of output depending on their performance.
Step-by-step explanation:
Frederick Taylor, a pioneer in the field of scientific management, developed the pay principle of differential piece-rate system based on his scientific management theory. This principle involved paying workers different rates per unit of output depending on their performance. Taylor believed that by implementing this system, it would incentivize employees to work more efficiently and increase productivity. An example of this principle in action was when Taylor showed that workers handling heavy iron ingots could be more productive by taking work rests, which resulted in increased wages for workers.