Reassessing cumulative self-paced reading (SPR): Testing three variants shows cumulative SPR can be more useful than...

Self-paced reading (SPR) is widely used to investigate real-time sentence processing. In SPR, sentences can be presented either cumulatively, with previously presented words remaining visible, or non-cumulatively, with previous words disappearing. However, most prior research has avoided cumulative presentation, largely due to concerns that it allows readers to reveal multiple words through rapid key presses and then read them, thereby undermining the interpretability of reading times. As a result, cumulative SPR is widely assumed to be unsuitable for research on real-time sentence processing. The present study examines this assumption by comparing three cumulative SPR variants-ahead-visible cumulative SPR (AVC-SPR), non-ahead-visible cumulative SPR (NAVC-SPR), and partially cumulative SPR (PC-SPR)-with standard non-cumulative SPR (NC-SPR). In AVC-SPR, the positions of upcoming words are visually indicated; in NAVC-SPR, upcoming positions are not indicated; and in PC-SPR, upcoming positions are likewise not indicated, and accumulation is capped so that only a limited number of words remain visible. The four tasks were compared in terms of their sensitivity to detecting garden-path and number-mismatch effects. Clear effects were observed in all four tasks, with NAVC-SPR yielding the largest effect sizes. Power analyses further indicated that NAVC-SPR generally offers the highest prospective power to detect these effects. PC-SPR showed effect sizes similar to or larger than those in NC-SPR, and AVC-SPR was the least reliable task. Together, these findings challenge the assumption that cumulative presentation is unsuitable for studying real-time sentence processing and suggest that NAVC-SPR and PC-SPR are viable alternatives to NC-SPR. All cumulative SPR tasks, together with an R script for automated stimulus formatting, are openly available to facilitate their adoption.