Negative polarity illusions are robust with both 'ever' and 'any' (when linear position is held constant)

Many studies have used linguistic illusions to probe the representations and mechanisms used during incremental language comprehension. A crucial component of this research program is mapping out when illusions occur and when they do not. To this end, we investigate the generality of a linguistic illusion observed with negative polarity items (NPIs). Most previous work has only investigated the illusion using a single NPI, ever (or its analogue in other languages), but all models of the illusion phenomenon implicitly predict that illusions should generalize across different NPIs. In apparent contradiction to this prediction Parker and Phillips (2016) found reliable illusions with ever, but not with the previously untested NPI any. In their original paper, the authors suggested that the asymmetry stemmed from differences in the linear position of the two NPIs in their test items. However, the authors did not establish the basic empirical generalization that any is, in fact, susceptible to the illusion when the confound of linear position is factored out. As such, their findings are equally compatible with the hypothesis that there is fine-grained lexical variation in inherent susceptibility to the illusion, which would have serious implications for all theories of the phenomenon. To settle the empirical record, we conducted a higher-power study comparing ever and any using items adapted from Parker and Phillips (2016) such that the two NPIs occupied the same ordinal position in their test sentences. We find comparable illusions for both NPIs, a welcome result for all candidate theories of the phenomenon and consistent with the distance-based explanation for its absence in Parker and Phillips (2016).