Frequency and predictability effects in eye fixations for skilled and less-skilled deaf readers

Abstract

The illiteracy rate in the deaf population has been alarmingly high for several decades, despite the fact that deaf children go through the standard stages of schooling. Much research addressing this issue has focused on word-level processes, but in the recent years, little research has focused on sentence-levels processes. Previous research (Fischler, 1985) investigated word integration within context in college-level deaf and hearing readers in a lexical decision task following incomplete sentences with targets that were congruous or incongruous relative to the preceding context; it was found that deaf readers, as a group, were more dependent on contextual information than their hearing counterparts. The present experiment extended Fischler's results and investigated the relationship between frequency, predictability, and reading skill in skilled hearing, skilled deaf, and less-skilled deaf readers. Results suggest that only less-skilled deaf readers, and not all deaf readers, rely more on contextual cues to boost word processing. Additionally, early effects of frequency and predictability were found for all three groups of readers, without any evidence for an interaction between frequency and predictability.

Keywords:

• Deaf readers
• Eye movements
• Frequency effects
• Predictability effects
• Reading skill

Acknowledgements

The research was supported by a FQRSC (125964) Postdoctoral Fellowship and by an NIDCD Grant (R03DC011352) to NNB, and National Science Foundation Science of Learning Center Program under cooperative agreement number SBE 1041725 to KR. The authors wish to extend their gratitude to all the participants in this study, and to Jesse “Rupert” Dubler and Jullian Zlatarev for invaluable help in participant recruitment and data collection. We thank Bernhard Angele and Klinton Bicknell for help with data analysis along with Timothy Slattery, Hazel Blythe, Simon Liversedge, and Albrecht Inhoff for their constructive comments on an earlier version of the manuscript.

Notes

¹Hand et al. (2010) investigated the Frequency×Predictability interaction as a function of launch sites of fixations before fixating the targets. They found a significant interaction in the single fixation duration data between frequency and predictability only when the launch sites from the words preceding the targets were 1–3 characters away from the target. This interaction suggested that predictability effects were larger for low frequency words than for high frequency words. When the launch sites from the word before the targets were 4–6 characters away from the target, the interaction was also significant but reversed with a larger predictability effect for the high frequency words than for the low frequency words. The interaction for launch sites even further away from the targets (7–9 characters) was not significant. Finally, a Frequency×Predictability interaction was found in the skipping data, suggesting, contrary to what was found for the fixation duration data, that only the high frequency words were affected by context predictability. Slattery et al. (2012), however, questioned Hand et al.'s statistical analyses; they performed similar analyses (Frequency×Predictability×Launch site) on two data sets but did not replicate Hand et al.'s results.

²The goal of the present experiment was to specifically compare skilled deaf readers to skilled hearing readers and then to compare less-skilled deaf readers to the skilled deaf readers. We therefore did not include a group of less-skilled hearing readers. Additionally, note that it would be unlikely to find a group of nondyslexic hearing readers matched on age, reading level (sixth-grade level) and nonverbal IQ, to the less-skilled deaf readers.