Can the resource reduction hypothesis explain sentence processing in aphasia? A visual world study in German

Resource limitation has often been invoked as a key driver of sentence comprehension difficulty, in both theories of language-unimpaired and language-impaired populations. In the field of aphasia, one such influential theory is Caplan’s resource reduction hypothesis (RRH). In this investigation of online processing in German, we evaluated three key predictions of the RRH in 21 individuals with aphasia and 50 control participants. Measures of online processing were obtained by combining a sentence-picture matching task with the visual world paradigm. Four sentence types were used to investigate the generality of the findings, and two test phases were used to investigate RRH’s predictions regarding variability in aphasia. The processing patterns were consistent with two of the three predictions of the RRH, with mixed conclusions for the third prediction. This study constitutes the first relatively large-scale investigation in German of the impact of resource reduction on sentence processing in aphasia.