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WORD LENGTH AND FREQUENCY EFFECTS ON CHILDREN'S EYE MOVEMENTS DURING READING ALOUD
Skuratova Ksenia Andreevna, St. Petersburg State University, St. Petersburg, E-mail: [email protected]
Kovaleva Valeria Alekseevna, St. Petersburg State University, St. Petersburg, E-mail: Valeria. kovaleva9419@gmail. com
Aderkas Anton Maksimovich, St. Petersburg State University, St. Petersburg, E-mail: [email protected]
Abstract. The study is devoted to the analysis of the effect of word lexical properties on the oculomotor activity of second-grade students with dyslexia. The results showed that the greatest number of fixations and observations, as well as longer observation lengths, are characteristic of low-frequency and long words, compared to high-frequency and short words. This pattern is characteristic both for dyslexic children and for children without reading disabilities, however it is most pronounced in children with dyslexia.
Key words: dyslexia, eye movements, word frequency, word length.
Studies of eye movements are carried out in different directions, however one of the key questions remains to be the role of eye movements in cognitive processes, in particular in reading. Reading - is a complex cognitive process where among the most important components are visual perception and extraction of information from text. Oculomotor (eye movement) activity allows to study these processes. Numerous studies have shown the possibility of using eye movements as an indicator of cognitive processes [6]. It has been proven that the parametric characteristics of eye movements are determined both by the muscular activity of the oculomotor apparatus and by the cognitive processes which provide the execution of reading. Changes in those characteristics during the process of ontogenesis are associated with the age-related changes (maturation) of cognitive functions (perception, attention, memory, thinking, etc.) as well as with the development and modification of the reading process mechanisms [1]. Currently, eye movements during the reading process are viewed as a reflection of complex cognitive processes, mainly tied to the text perception, its semantic analysis and information processing. At the same time, changes in the main parameters of eye movements (temporal and spatial) are associated with effect of various textual properties and visual information processing [2; 3]. According to many
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models of the reading process, parameters of oculomotor activity are affected by graphical [4; 5], linguistic [7; 8] properties of words and / or text itself.
Research methods
Five texts were used as a stimulus material in this study Texts had similar length (55 words), theme and complexity. 95 second grade students of general education schools from St. Petersburg participated in the study: 22 students with dyslexia and 55 without any reading disabilities. Each subject was asked to read aloud five texts presented in random order on the computer monitor. Eye movements were recorded using eye tracker.
Results:
For the analysis of the effect of students' reading skills and word lexical properties, as well as the interaction of these factors, multifactorial ANOVA was used. The results are presented in Table 1.
Table 1
The effect of reading skill, frequency and word length on the parameters of the oculomotor activity (multifactorial ANOVA results)
effect fixation count observat ion count observation length
F P F p F P
group 162.311 0.000 82.105 0.000 164.363 0.000
frequency 16.989 0.000 9.885 0.000 24.406 0.000
length 11.503 0.000 3.955 0.021 10.266 0.000
group * frequency 3.832 0.005 2.614 0.036 7.338 0.000
group * length 4.421 0.013 0.266 0.767 4.785 0.009
frequency * length 1.508 0.166 0.678 0.691 2.407 0.022
It was found that the smallest number of fixations is characteristic of high-frequency words (i.e., the most common words in the language), as well as short words (p <0.001). The number of fixations increases as the frequency of words decreases and their length increases (from 1.7 to 12.1 fixations for students with dyslexia; from 1.1 to 5.9 fixations for students without reading disabilities).
The reading skill also has a statistically significant effect on the number of fixations (p <0.001). The average number of fixations for students with dyslexia is 6.1 ±2.1, for students without reading disabilities, 2.8 ± 1.1.
The effect of word frequency and length on the number of fixations depending on the reading skill is shown in Figures 1 and 2.
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9 8 7
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frequency:
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2 - 10-100 ipm
3 - 100-500 ipm
4 - 500-1000 ipm
5 - 1000-2500 ipm
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frequency
Fig. 1 The word frequency effect on the fixation count
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length: 1-2-5 letters 2 - 6-8 letters 3-9-14 letters
length
Fig. 2 The word length effect on the fixation count
The study found that the highest number of observations associated with the revisits to previously read words is typical for low-frequency and long words (p <0.001 and p <0.05, respectively). The number of observations becomes lower as the frequency of words increases and their length decreases (from 6.4 to 1.3 observations for students with dyslexia; from 3.3 to 1.1 views for students without reading disabilities).
The reading skill also has a statistically significant effect on the number of observations (p <0.001). Students with dyslexia often have to make regressive saccades and return to previously read words: the average number of observations for
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students with dyslexia is 3.7 ± 1.2, and 2 ± 0.7 for students without reading disabilities.
The effect of word frequency and length on the observation count, depending on the reading skill, is shown in Figures 3 and 4.
2 3 4
frequency
Fig. 3 The word frequency effect on the observation count
Fig. 4 The word length effect on the observation count
The analysis of the obtained data showed that the shortest observation length are characteristic of high-frequency words and short words (p <0.001). The length of the observations increases as the frequency of words decreases and their length increases (from 0.8 s to 7.6 s for students with dyslexia; from 0.7 s to 3.2 s for students without reading disabilities).
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The reading skill also has a statistically significant effect on the observation length (p <0.001). The average observation length for students with dyslexia 3.4 ± 1.3 s, for students without reading disabilities, 1.5 ± 0.5 s.
The effect of word frequency and length on the observation length, depending on the reading skill, is shown in Figures 5 and 6.
5.5 5,0 4.5 4.0 3,5 3.0 2,5 2,0 1,5 1 0 0.5
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5control group StJyslexia
frequency 1 - 0.5-10 ipm
2-10-100 ipm
3- 100-500 ipm
4- 500-1000 ipm
5- 1000-2500 ipm
frequency
Fig. 5 The word frequency effect on the observation length
Fig. 6 The word length effect on the observation length
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Conclusions:
The results of this study showed the effect of word length and frequency on the oculomotor activity of second-grade students when reading aloud: the smallest number of fixations and observations, as well as shorter observation length, were found to be characteristic of high-frequency and short words. On the contrary, when reading low-frequency and long words, students make a higher number of fixations and observations, and the observation length is longer. Moreover, the effect of the reading skill was also revealed: students with dyslexia make a higher number of fixations and observations and have longer observation lengths than students without reading disabilities.
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