Eye Movements Evidence Of New Word Learning Ability In Children With Developmental Dyslexia

Developmental dyslexia is a specific learning disability despite normal intelligence and access to conventional instruction.It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities.While there is no obvious brain deficits,mental disorder or visual impairments,dyslexics show lower reading level than their chronological age controls.Previous studies have shown that children with developmental dyslexia have difficulty in word recognition,and their vocabulary is obviously lower than normal children’s.Literacy is a key indicator for screening children with developmental dyslexia.Learning new words from context during natural reading is an important way of children’s vocabulary growth.Is this due to the poor efficiency of vocabulary acquisition in natural reading?Previous studies have found that as an unambiguous visual cue to word boundaries,word spaces in Chinese text facilitate vocabulary acquisition of adults and children,and the magnitude of the promotion is influenced by the reader’s reading ability.Because of the lower reading ability,whether children with developmental dyslexia are more reliant on a visual cue to word boundaries than normal children?Therefore,using new word learning paradigm,this study discussed the above mentioned questions through two experiments.Experiment 1 mainly investigated different eye movement paterns of vocabulary acquisition between children with developmental dyslexia and normal children in natural reading.The subjects were children with developmental dyslexia(DD)and their matched controls including chronological age(CA)group and reading level controls(RL)group.All participants were screened from the grade 3 and 5 in four primary schools.Participants were instructed to read the sentences normally and try to learn the meaning of the new words.Eyelink1000 was used in this experiment.The results showed that:(1)DD and its matching group could form semantic category representation of new words by reading 8 contexts.(2)With the increase of learning times,the time for all children to look at new words appeared a decreasing trend,but the decline of DD is significantly later than that of matched group children in early eye movement index.(3)With no delaying,the decline of DD is significantly slower than that of matched group children in late eye movement index.The results proved that the vocabulary acquisition ability during the natural reading of children with developmental dyslexia is lower than that of normal children,that was mainly reflected in the early processing of new words.Experiment 2 aimed to explore whether providing visual word segmentation clues would improve the learning ability of new words in children with developmental dyslexia.Eyelink1000 was used in this experiment.New words were divided into two groups—half words were embedded into these learning sentences as normal text,while the other half of the words were embedded into the learning sentences as spaced text.All participants read both normal text and spaced text.The results showed that inserting spaces between words could improve the efficiency of new words learning in three groups of children,but they were different in the size and way of promotion effect.Details as follows:The promotion of space was manifested in the whole processing stage of new word learning for DD,in the late semantic integration stage for CA,and in part of the early stages and the late semantic integration stage for RL.To summarize the findings of these two studies,the conclusion was made as follows:(1)Children with developmental dyslexia showed a low efficiency in new word learning,which was mainly reflected in early processing of visual characteristics of new words.(2)Word spaces could promote all children’s new words learning,and promote DD most effectively.In conclusion,our experiments provide new experimental evidence for the low vocabulary acquisition ability of Chinese children with developmental dyslexia and contribute to the exploration of effective ways to improve their vocabulary acquisition ability.