For most individuals. nicotine appears to be the most important component of the affect-modulating properties of tobacco use. Because there is a great similarity between tobacco withdrawal symptoms and the negative affective states that nicotine and tobacco use alleviate (Hughes. Hatsukami. Pickens. Krahn. Malin. & Luknic. 1984). a fundamental question is whether nicotine has mood and performance-enhancing effects above and beyond those associated with withdrawal symptom alleviation. It is necessary to determine whether these effects arise from withdrawal alleviation. from inherent properties of nicotine. or from various interactions and combinations of environmental. conditioning. pharmacological. and sensory parameters.