Kendra taught her 4-year-old cousin how to do jumping jacks. first she rewarded him for jumping up and down on the spot. then she rewarded him for jumping up and down while alternating wide-leg landings with narrow-leg landings. finally she rewarded him for doing this kind of jumping while also raising his arms from his sides in time to each of his wide-legged jumps. this learning strategy best illustrates the process of: