This study investigated the claims of career of metaphor hypothesis (Gentner and Bowdle, 2001; Bowdle and Gentner, 2005) and dual reference theory (Glucksberg and Haught, 2006a; 2006b) regarding the role of comparison and categorization in metaphor processing and polysemy. Career of metaphor hypothesis suggests that conventionality of the base term plays a significant role on whether a figurative statement will be processed through comparison or categorization, conventional figurative statements being more likely to be processed through categorization than novel ones. Dual reference theory suggests that, regardless of conventionality, the main factor that would determine how a figurative statement is processed is whether it is presented as a metaphor or a simile. The two theories also offer different accounts regarding the relationship between metaphor processing and polysemy. Career of metaphor hypothesis suggests that conventional base terms have two meanings, one of which refers to a metaphoric, domain general category. Dual reference theory suggests that base terms of all apt metaphors have two meanings: the original, literal meaning and the metaphoric meaning which refers to a metaphor-appropriate ad hoc category. The experiments produced support for the career of metaphor view that conventional statements are more likely to be processed through categorization. Experiment I revealed that interpretations of conventional statements contained a greater number of cues indicating processing through categorization. Experiment II showed that subjects had a preference for a given order of the target and the base in conventional statements, but this preference was not as strong for novel statements. Strong preference for a certain order of the target and the base is a property of literal categorization statements. Sensibility judgments of Experiment IV indicated that conventional metaphors were rated as sensible as conventional similes whereas novel metaphors were rated as less sensible than novel similes. This finding is also compatible with the career of metaphor hypothesis. The implications of these findings regarding metaphor comprehension and polysemy and future directions for research are discussed.