The study of expertise in surgery aims to facilitate the development of improved training methods by understanding the characteristics of expert practitioners. In this article and its companion, we present our study of the characteristics of competence and expertise in the field of oral surgery. We observed participants of different skill levels as they performed an ex vivo drilling task designed to test the psychomotor skill of distinguishing the material boundaries between tooth and bone. Part 1 of this study examined the physical characteristics of drilling performance, while this article examines the cognitive aspects of performance. In this article we investigate the psychomotor cues used for decision making during drilling and explore other factors that affect a participant's ability to distinguish tooth from bone. Our results suggest that visual and tactile cues were the most important cues guiding drilling performance in all participant groups. Our results also suggest that when compared to experts, novices relied more on visual cues rather than tactile cues and lacked the psychomotor skills required to utilize the broader range of cues used by experts.