We compared effects of covert spatial-attention shifts induced with exogenous or endogenous cues on microsaccade rate and direction. Separate and dissociated effects were obtained in rate and direction measures. Display changes caused microsaccade rate inhibition, followed by sustained rate enhancement. Effects on microsaccade direction were differentially tied to cue class (exogenous vs. endogenous) and type (neutral vs. directional). For endogenous cues, direction effects were weak and occurred late. Exogenous cues caused a fast direction bias towards the cue (i.e., early automatic triggering of saccade programs), followed by a shift in the opposite direction (i.e, controlled inhibition of cue-directed saccades, leading to a 'leakage' of microsaccades in the opposite direction).

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Using the gaze-contingent boundary paradigm with the boundary placed after word n, we manipulated preview of word n+2 for fixations on word n. There was no preview benefit for first-pass reading on word n+2, replicating the results of Rayner, Juhasz, and Brown (2007), but there was a preview benefit on the three-letter word n+1, that is, after the boundary, but before word n+2. Additionally, both word n+1 and word n+2 exhibited parafoveal-on-foveal effects on word n. Thus, during a fixation on word n and given a short word n+1, some information is extracted from word n+2, supporting the hypothesis of distributed processing in the perceptual span.Key words: eye movements, reading, preview benefit, parafoveal-on-foveal effects Preprocessing word n+2 3 Two competing hypotheses organize much current research on eye-movement control during reading: (a) parallel lexical processing of words in the perceptual span with efficiency decreasing with eccentricity of words relative to the point of fixation and (b) strictly serial word-by-word processing with sequential shifts of attention. The differences between these positions are much more graded than this simple dichotomy suggests (for recent presentations see, e.g., Engbert, Nuthmann, Richter, & Kliegl, 2005;Inhoff, Eiter, & Radach, 2005;Kliegl, Nuthmann, & Engbert, 2006;Kliegl, 2007;McDonald, Carpenter & Shillcock, 2005;Pollatsek, Reichle, & Rayner, 2006;Pynte & Kennedy, 2006).A critical empirical question for all theoretical proposals is the spatial extent of the influence of parafoveal words. The perceptual span, a region extending three to four letters to the left and up to fifteen letters to the right of fixation, sets the outer limits (McConkie & Rayner, 1975;Rayner & Bertera, 1979). Letter-specific information, however, is extracted only up to seven or eight letters to the right (e.g., Rayner, 1998, for a review). Granting preview of word n+1 during a fixation on word n facilitates later processing of word n+1.This preview benefit is measured with the boundary paradigm, where a critical word in the direction of reading is only revealed when the eyes cross the space before it (Rayner, 1975). There is also evidence that sublexical or lexical properties of word n+1 influence the fixation on word n. Comprehensive reviews of this controversial debate from different perspectives can be found in Inhoff, Radach, Starr, and Greenberg (2000), Kennedy (2000), Kennedy, Pynte, and Ducrot (2002), and Rayner, White, Kambe, Miller, and Liversedge (2003). went beyond earlier research and examined preview benefit on a target word with boundaries placed either after the preceding word (n+1 preview condition) or even the word preceding it (n+2 preview condition). There were preview benefits in the former but no preview benefits in the latter case and there were no parafoveal-on-foveal Preprocessing word n+2 4 effects in two experiments. 1 These results were interpreted to favor models like E-Z Reader that expect preprocessing of word n+2 only under very specific circumstance...

Eye movements in reading are sensitive to foveal and parafoveal word features. Whereas the influence of orthographic or phonological parafoveal information on gaze control is undisputed, there has been no reliable evidence for early parafoveal extraction of semantic information in alphabetic script. Using a novel combination of the gaze-contingent fast-priming and boundary paradigms, we demonstrate semantic preview benefit when a semantically related parafoveal word was available during the initial 125 ms of a fixation on the pretarget word (Experiments 1 and 2). When the target location was made more salient, significant parafoveal semantic priming occurred only at 80 ms (Experiment 3). Finally, with short primes only (20, 40, 60 ms), effects were not significant but were numerically in the expected direction for 40 and 60 ms (Experiment 4). In all experiments, fixation durations on the target word increased with prime durations under all conditions. The evidence for extraction of semantic information from the parafoveal word favors an explanation in terms of parallel word processing in reading.

Processing in our visual system is functionally segregated, with the fovea specialized in processing fine detail (high spatial frequencies) for object identification, and the periphery in processing coarse information (low frequencies) for spatial orienting and saccade target selection. Here we investigate the consequences of this functional segregation for the control of fixation durations during scene viewing. Using gaze-contingent displays, we applied high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition. In contrast with predictions from functional segregation, fixation durations were unaffected when the critical information for vision was strongly attenuated (foveal low-pass and peripheral high-pass filtering); fixation durations increased, however, when useful information was left mostly intact by the filter (foveal high-pass and peripheral low-pass filtering). These patterns of results are difficult to explain under the assumption that fixation durations are controlled by foveal processing difficulty. As an alternative explanation, we developed the hypothesis that the interaction of foveal and peripheral processing controls fixation duration. To investigate the viability of this explanation, we implemented a computational model with two compartments, approximating spatial aspects of processing by foveal and peripheral activations that change according to a small set of dynamical rules. The model reproduced distributions of fixation durations from all experimental conditions by variation of few parameters that were affected by specific filtering conditions.