Utilizing the two-dimensional plane of valence and arousal with multi-dimensional scaling (MDS), the current study sought to better understand the structure of affect and the relationship between emotion items. The positive and negative affect schedule (PANAS) is the most frequently applied self-report measure of affect but has been criticized for only including high arousal emotions. A between-subjects, two-part experimental study was conducted. Participants (N = 548) were recruited online and asked to rate the similarity between one of two target words (anger: n = 271; calm: n = 277) and 143 emotion words. Our results provided evidence for the two-dimensional plane of valence and arousal, indicating that all four quadrants are important when studying affect. Overall, the current study found support for the activation-arousal theory of affectivity with MDS analyses. Emotion words clustered in all four quadrants of the two-dimensional plane, demonstrating the necessity of an affect measure that encompasses all four quadrants. Furthermore, our results demonstrated that the PANAS does not include items in the positive valence/low activation quadrant, however, a newly published measure was found to have increased item dispersion, with items included in all four quadrants of affect. Limitations and proposed future directions are discussed.