In our prior research, we examined the identification of two-noun Finnish compound words by embedding them in sentence contexts and recording readers' eye movements on these compounds while they read the sentences for comprehension. (In Finnish, compound words are never broken by interword spaces.) The results suggest that long (12-to 18-letter) compound words are processed primarily in such a way that the constituents are processed serially (from left to right). Hyönä and Pollatsek (1998) manipulated the frequency of the first constituent (i.e., its frequency as a separate word) while matching for second-constituent and whole-word frequency (e.g., liikenne in liikennevalo ϭ traffic light). They observed that first-constituent frequency had both an early effect that surfaced in the duration of the initial fixation on the word and a later, larger effect on the gaze duration on a word (the total first pass time on the word), which was due largely to differences in the number of times that the word was fixated. Both of these effects were subsequently replicated by Bertram and Hyönä (2003) for long compounds. Pollatsek, Hyönä, and Bertram (2000) also observed that the frequency of the second constituent had a large effect on the gaze duration on the compound word. However, second-constituent frequency did not affect the duration of first fixation on the compound but affected processing starting only on the second fixation. These data are consistent with the view that long compounds are identified serially via their constituents by first accessing the initial constituent, followed by the access of the second constituent (for other eye movement studies of compound word processing in reading, see Andrews, Miller, & Rayner, 2004;Inhoff, 1989a;Inhoff, Briihl, & Schwartz, 1996;Inhoff, Radach, & Heller, 2000;Juhasz, Starr, Inhoff, & Placke, 2003). However, since Pollatsek and Hyönä (in press) demonstrated that both the gaze durations and the first-constituent frequency effects were the same for semantically opaque compounds as for semantically transparent compounds, it appears that the initial stages of the composition of the two constituents does not involve integrating their meanings.There are data, however, indicating that accessing a compound word is more than a serial identification of its components. In particular, when the frequency of the compound word was varied (while equating the frequency of the constituents), there were also large effects on the gaze duration on the compound word , although the effect of word frequency was not significant until the second fixation. This word frequency effect indicates that more holistic processing of the compound words is occurring as well. Moreover, Bertram and Hyönä (2003) found that a compositional mode of processing may be important only for relatively long compound words. For shorter compound words (7-9 characters), they obtained an early effect of word frequency but
523Copyright 2004 Psychonomic Society, Inc.This research was supported by an Academy of Finland grant to t...