The primary hypothesis of this study is that the administration of a prompt to perform a relaxation exercise as compared to no prompt will lead to a lower likelihood of being stressed in the subsequent two hours, and that this effect will be stronger when the prompt is administered when the individual is stressed. The secondary hypothesis is that stress episodes will predict the timing of smoking lapses. The third hypothesis is that administration of a prompt to perform a relaxation exercise will reduce the odds of smoking for the next two hours, and that this effect will be stronger when the prompt is administered when the individual is stressed. The fourth (exploratory) hypothesis is that stress will predict the timing of overeating episodes.