Word length and frequency effects on children’s eye movements during silent reading

•Word length and frequency effects on eye movements were found for silent reading.•Word length and frequency effects were greater for children than adults.•The interaction of word length and frequency was significant for children.•This interaction can be mapped onto the interplay of lexical and sublexical processes.

In the present study we measured the eye movements of a large sample of 2nd grade German speaking children and a control group of adults during a silent reading task. To be able to directly investigate the interaction of word length and frequency effects we employed controlled sentence frames with embedded target words in an experimental design in which length and frequency were manipulated independently of one another. Unlike previous studies which have investigated the interaction of word length and frequency effects in children, we used age-appropriate word frequencies for children. We found significant effects of word length and frequency for both children and adults while effects were generally greater for children. The interaction of word length and frequency was significant for children in gaze duration and total viewing time eye movement measures but not for adults. Our results suggest that children rely on sublexical decoding of infrequent words, leading to greater length effects for infrequent than frequent words while adults do not show this effect when reading children’s reading materials.