The effect of age of acquisition and imageability on reading words aloud

The age at which words are learned appears to affect the speed at which they can be accessed in various tasks. This age of acquisition (AoA) effect is argued by some to be a semantic one; however, more explicitly semantic variables such as imageability are rarely found to have an effect on reading words aloud, and only under particular circumstances. This study explores the potential interaction between the two variables. AoA estimates by adult readers were found to be reliable for different word sets with different levels of imageability. Words varying on AoA and imageability but matched on other variables in a factorial design were then read aloud by skilled adult readers in either mixed blocks, or in pure blocks of high or low imageability. An AoA effect was found when words were presented in the mixed blocks, but no imageability effect was found. By contrast, an imageability effect was found across the pure blocks, and the AoA effect was significant within the high imageability block. The results are discussed in terms of two hypotheses relating to strategic control of processing in pure and mixed blocks, the route emphasis account and input gain