Relative clause extractions generally yield so-called island effects (degraded judgments) across languages (Ross 1967), (1). However, Swedish and the other Mainland Scandinavian languages comprise famous exceptions to this pattern (e.g. Engdahl & Ejerhed 1982), cf. (2).

(1) *Those kind of books I know a girl that writes.

(2) Såna böcker känner jag en tjej som skriver.

The origin of island effects is under debate. Sprouse et al. (2012) found superadditive effects in judgments of island violations in English – combined effects greater than the sum of the individual costs for extraction and complexity (island structure). Because no correlation was found between participants' memory span (measured via serial recall and n-back) and the superadditive effects, they concluded that island effects must be derived from violations of syntactic constraints rather than processing limitations. In contrast, Hofmeister et al. (2014) did find a correlation between working memory span (measured via reading span) and superadditivity in a rapid serial visual representation experiment. They also found superadditive effects in fully grammatical, but hard to process sentences, suggesting that processing factors do play a role in superadditivity and hence in island effects.

In our talk, we report on the results from an acceptability judgment experiment that was designed to look for superadditive effects in judgments of relative clause extractions in Swedish, to help determine whether these structures – even though claimed to be acceptable – behave like other island violations with regard to superadditivity. If they do, then this would reduce some of the exceptionality of their status. In the experiment, we investigated the (super)additive effect of clause type (TC vs. RC) and extraction type (long vs. short) on acceptability ratings, and tested whether any such effects correlate with memory span, as measured via an n-back and a reading span task. Our expectation was that the latter test would provide a much better marker of WM than the former.

Det var Anna som anmälde en kille som snattade såna chokladkakor i godisaffären. RC + ShortExt Det var Anna som anmälde att en kille snattade såna chokladkakor i godisaffären. TC + ShortExt Det var såna chokladkakor som Anna anmälde en kille som snattade i godisaffären. RC + LongExt Det var såna chokladkakor som Anna anmälde att en kille snattade i godisaffären. TC + LongExt