PCA indicated that the random intercept for participants and the random slope for the identity of the poet were unnecessary and were causing the overparameterization. This conclusion is borne out in the data; looking at the proportion of “written by a human” responses for each participant, the variance is only 0.021; the variance between poets is only 0.00013. The lower-than-expected variance in the data simply does not support the complex random-effects structure. We therefore fit a reduced model with random intercepts for poems as the only random effect. Using ANOVA to compare model fit, we found that the full model containing our original set of random effects (npar = 76, AIC = 22385, BIC = 22970, logLik = -11116) did not provide a significantly better fit than the reduced model (npar = 21, AIC = 22292.5, BIC = 22454.2, logLik = -11125.2). We therefore proceed with the reduced model.