Real-time resolution of VP ellipsis ambiguity and processing depth

In the VP ellipsis sentence "Bill liked himself, and John did too," the second conjunct "John did too" can be interpreted in two ways: either as "John liked Bill too" (strict interpretation) or "John liked himself too" (sloppy interpretation). Previous research has yielded inconclusive findings regarding which interpretation is preferred during real-time sentence processing. To investigate potential causes of these mixed findings, we conducted three reading experiments (Experiments 1-3) testing whether the inconclusive results could be attributed to (i) insufficient statistical power, (ii) limitations in experimental materials, or (iii) the influence of processing depth. We also examined whether form mismatches (e.g., "herself/himself") affect the resolution of VP ellipsis ambiguities, as in "Mary liked herself, and John did [_ellipsis like himself] too". Experiment 1, with a large sample size (360 participants), showed no clear preference for either interpretation. Experiment 2, using revised materials, revealed a preference for the strict interpretation. Experiment 3 included comprehension questions targeting the interpretation of the elided material to assess the influence of processing depth. Results indicated that participants who answered correctly preferred the strict interpretation, while those who answered incorrectly preferred the sloppy interpretation. Across all three experiments, form mismatches produced no clear effect. We propose an account of the mechanisms underlying the real-time resolution of VP ellipsis ambiguities and discuss how processing depth influences preferences for the strict or sloppy interpretation.