Morphological effects in word identification: tracking the developmental trajectory of derivational suffixes in Spanish Miguel La ´zaro 1 • Vı ´ctor Illera 1 • Joana Acha 2 • Ainoa Escalonilla 1 • Seila Garcı ´a 1 • Javier S. Sainz 1 Ó Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract The role of morphological processing has been shown to be highly rel- evant in learning to read. However, there is little evidence on the processing of derivational suffixes from a developmental perspective. The aim of this study is to assess the developmental emergence of suffixes as meaningful processing units in word recognition. To that aim, 96 children from fourth, fifth and sixth grade, as well as adults, took part in a masked priming lexical decision task (go/no-go version). Complex and simple words were primed by other words sharing the suffix (as in lechero/milkman/- [ jornalero/laborer/) and word ending (as in aran ˜ a/spider/- [ Espan ˜ a/Spain/) or by words not sharing an ending (surfista/surfer/- [ jornalero/ laborer/; carpeta/folder/- [ Espan ˜a/Spain/). Results in adults replicate previous studies by showing that only the related condition of complex words elicits a sig- nificant facilitation (see Dun ˜abeitia, Perea, & Carreiras, 2008). With respect to children, only sixth graders generated a similar pattern to adults. Children in fourth and fifth grade showed no morphological effect. Our data reveal a progressive & Miguel La ´zaro miguel.lazaro@ucm.es Vı ´ctor Illera victor.illera@gmail.com Joana Acha Joana.acha@ehu.eus Ainoa Escalonilla ainoa0803@hotmail.com Seila Garcı ´a seila_ggomez@hotmail.com Javier S. Sainz jsainz@psi.ucm.es 1 Universidad Complutense de Madrid, Madrid, Spain 2 Universidad del Paı ´s Vasco/Euskal Herriko Unibertsitatea, Donostia, Spain 123 Read Writ https://doi.org/10.1007/s11145-018-9858-1