How does Stroop interference change with practice? A reappraisal from the musical Stroop paradigm

Most earlier studies investigating the evolution of the Stroop effect with the amount of reading practice have reported data consistent with an inverted U-shaped curve, whereby the Stroop effect appears early during reading acquisition, reaches a peak after 2 or 3 years of practice, and then continuously decreases until adulthood. The downward component of the curve suggests that skilled performers would be able to control their performance better than less-skilled performers. However, in these studies, the level of reading practice entirely coincides with age due to obvious practical and ethical constraints, and it is possible that the observed reduction in the Stroop interference is due to a growing ability of older children to inhibit nonrelevant information. In the present study, word reading, as source of interference, was replaced by note naming in musicians. The major advantage is that musical training can be easily decoupled from age. In 2 experiments exploiting the musical Stroop paradigm (Grégoire, Perruchet, & Poulin-Charronnat, 2013), we observed an early appearance of the interference effect, as reported for the color-word and picture-word Stroop tasks, but we did not replicate the inverted U-shaped curve. Experiment 2 revealed a linear and positive relation between the amplitude of the musical Stroop effect and the amount of musical practice across 5 years of musical training. These results suggest that reading practice in itself does not lead to increased control over reading and that the usual pattern of results is most likely due to the strong correlation between age and reading practice.