The effect of age of acquisition: Partly frequency-related, partly frequency-independent

A review of multitask investigations on the locus of the age-of-acquisition (AoA) effect in the English, Dutch, and French languages reveals two main findings. First, for the most tasks there is near perfect correlation between the magnitude of the AoA effect and the magnitude of the frequency effect, even though the stimuli were selected so that both variables were orthogonal. This frequency-related AoA effect is as large as the frequency effect, despite the fact that the range of AoA values is more restricted than the range of frequency values. Second, a frequency-independent AoA effect is observed in object naming and word associate generation. Different explanations of the frequency-related and the frequency-independent AoA effects are reviewed and evaluated