As an exploratory analysis, we also fit a model with our four factors Emotional Quality, Formal Quality, Atmosphere, and Creativity. We included authorship and these four factors as fixed effects, with random intercepts for participants. Effectively, this model replaces the structural features of the previous model (stimulus line count, stimulus all-lines-rhyme, and stimulus first-person) with qualitative features. The explanatory power of this model was higher (conditional R-squared: 0.240, marginal R-squared: 0.148), suggesting that qualitative features may have more influence than structural features on participants’ beliefs about a poem’s authorship.