Previous research has shown that words presented on metaphor congruent locations (e.g., positive words "up" on the screen and negative words "down" on the screen) are categorized faster than words presented on metaphor incongruent locations (e.g., positive words "down" and negative words "up"). These findings have been explained in terms of an interference effect: The meaning associated with "up" and "down" vertical space can automatically interfere with the categorization of words with a metaphorically incongruent meaning. The current studies test an alternative explanation for the interaction between the vertical position of abstract concepts and the speed with which these stimuli are categorized. Research on "polarity differences" (basic asymmetries in the way dimensions are processed) predicts that +polar endpoints of dimensions (e.g., positive, moral, "up") are categorized faster than -polar endpoints of dimensions (e.g., negative, immoral, "down"). Furthermore, the polarity correspondence principle predicts that stimuli where polarities correspond (e.g., positive words presented "up") provide an additional processing benefit compared to stimuli where polarities do not correspond (e.g., negative words presented "up"). A meta-analysis (Study 1) shows that a polarity account provides a better explanation of reaction time patterns in previous studies than an interference explanation. An experiment (Study 2) reveals that controlling for the polarity benefit of +polar words compared to -polar words did not only remove the main effect of word polarity but also the interaction between word meaning and vertical position due to polarity correspondence. These results reveal that metaphor congruency effects should not be interpreted as automatic associations between vertical locations and word meaning but instead are more parsimoniously explained by their structural overlap in polarities. (Contains 1 figure, 3 tables and 4 footnotes.)