The length of a complex word modifies the role of morphological structure: Evidence from eye movements when reading short and long Finnish compounds

This study explored whether the length of a complex word modifies the role of morphological structure in lexical processing: Does morphological structure play a similar role in short complex words that typically elicit one eye fixation (e.g., eyelid) as it does in long complex words that typically elicit two or more eye fixations (e.g., watercourse)? Two eye movement experiments with short vs. long Finnish compound words in context were conducted to find an answer to this question. In Experiment 1, a first-constituent frequency manipulation revealed solid effects for long compounds in early and late processing measures, but no effects for short compounds. In contrast, in Experiment 2, a whole-word frequency manipulation elicited solid effects for short compounds in early and late processing measures, but mainly late effects for long compounds. A race model, incorporating a headstart for the decomposition route, in case whole-word information of complex words cannot be extracted in a single fixation can explain the pattern of results.