The effects of length and transposed-letter similarity in lexical decision: evidence with beginning, intermediate, and adult readers.

Do length and transposed-letter effects reflect developmental changes on reading acquisition in a transparent orthography? Can computational models of visual word recognition accommodate these changes? To answer these questions, we carried out a masked priming lexical decision experiment with Spanish beginning, intermediate, and adult readers (N=36, 44, and 39; average age: 7, 11, and 22 years, respectively). Target words were either short or long (6.5 vs. 8.5 letters), and transposed-letter primes were formed by the transposition of two letters (e.g. aminal-ANIMAL) or by the substitution of two letters (orthographic control: arisal-ANIMAL). Children showed a robust length effect (i.e. long words were read slower than short words) that vanished in adults. In addition, both children and young adults showed a transposed-letter priming effect relative to the control condition. A robust transposed-letter priming effect was also observed in non-word reading, which strongly suggests that this effect occurs at an early prelexical level. Taken together, the results reveal that children evolve from a letter-by-letter reading to a direct lexical access and that the lexical decision task successfully captures the changing strategies used by beginning, intermediate, and adult readers. We examine the implications of these findings for the recent models of visual word recognition.