Bob decided that he was a bit overweight and in order to do something about it, he created a new exercise program, something he'd never tried before. Though he initially had some difficulty setting it up and sticking with it, he has consistently done his exercise workout for the last eight months. Though it is becoming more habitual, the program is still not yet automatic for him and he reinforces himself with new CDs each month if he has successfully completed his workouts. According to the stages of change model, Bob would most likely be in the _____.