The Matthew effect is often used as a metaphor to describe a widening gap between good
and poor readers over time. In this study we examined the development of individual
differences in reading and cognitive functioning in children with reading difficulties and
normal readers from Grades 1 to 3. Matthew effects were observed for individual
differences in reading comprehension and vocabulary, but not on tests measuring word
decoding, word recognition, or spelling, nor on non-verbal ability. However, these
Matthew effects disappeared when controlling for home literacy activities and parent
reading behavior, indicating that print exposure is one environmental condition involved
in mediating Matthew effects. These findings are in line with the idea of the Matthew
effect by Stanovich and the core assumption that reading comprehension is involved in
a reciprocal relationship with vocabulary knowledge.