exhibit LOW attachment. @fernadez2003bilingual found that English speakers had a LOW bias, preferring \[fullB\] over \[fullA\], while Spanish speakers had a HIGH bias, preferring \[fullC\] over \[fullD\].

We ran two experiments per language,[^3] one a direct simulation of the experiment from @fernadez2003bilingual and the other an extension (<span style="font-variant:small-caps;">Extended Data</span>), using a larger set of experimental stimuli. The direct simulation allowed us to compare the attachment preferences for RNN LMs to the experimental results for humans. The extension allowed us to confirm that any attachment preferences we observed were generalizable properties of these models.

Specifically, the <span style="font-variant:small-caps;">Extended Data</span> set of stimuli included the English and Spanish stimuli from @carreiras1993relative in addition to the stimuli from @fernadez2003bilingual, for a total of 40 sentences. Next, we assigned part-of-speech tags to the English and Spanish LM training data using TreeTagger [@schmid1999improvements]. We filtered the tokens to the top 40 most frequent plural nouns, generating the singular forms from TreeTagger’s lemmatization. We then substituted into the test sentences all combinations of distinct nouns excluding reflexives. Then we appended a relative clause with either a singular or plural verb (*was/were* or *estaba/estaban*).[^4] Finally, each test stimulus in a pair had a LOW and HIGH 