Prior evidence from masked morphological priming has
revealed conflicting findings regarding the acquisition of
morpho-orthographic segmentation mechanisms in developing
readers. Here, we examined changes in masked morphological
priming across grade within a large sample of French
primary school children (n = 191, Grades 2–5) and how these
effects are modulated by individual differences in reading
proficiency, spelling proficiency, and morphological awareness.
Target words were preceded by either (a) a suffixed word prime
(e.g., tristesse–TRISTE), (b) a suffixed nonword prime
(e.g., tristerie–TRISTE), (c) a non-suffixed nonword prime (e.g.,
tristald–TRISTE), or (d) an unrelated prime (e.g., direction–
TRISTE) using very short prime durations (50 ms). Moreover, a
frequency manipulation was included for suffixes and
non-suffixes. The results revealed robust suffixed word priming
across all children independent of grade and proficiency. On
the other hand, priming in the suffixed and non-suffixed nonword
conditions was modulated by reading proficiency, with
high-proficiency children showing facilitation and
low-proficiency children showing inhibition. The effects of suffix
and non-suffix frequency were modulated by grade, with
decreasing effects as grade increased. None of the observed
priming effects were modulated by grade, spelling proficiency,
or morphological awareness. The results suggest that reading
proficiency is an important predictor for embedded stem