Differences in Toddlers' inhibitory control performance across phases with and without sound-absorbing materials in a nursery classroom: a field-based intervention study.

OBJECTIVE

To examine whether toddlers' IC-related performance differed across classroom periods with and without sound-absorbing materials.

METHODS

A field-based alternating intervention was conducted in a Japanese nursery classroom (N = 30; age = 24.3-39.3 months). Sound-absorbing materials were installed during two phases and removed during an intervening phase. Existing classroom recordings from four days in each phase were analyzed to characterize sound levels and reverberation times were measured across two phases. IC was assessed using a delay-of-gratification task and analyzed using logistic mixed-effects models. Teachers also completed the Self-Regulation Assessment Scale for Early Childhood for a subset of children.

RESULTS

Modest reductions in reverberation time and sound levels were observed during the phases with the sound-absorbing materials installed.　Children showed significantly higher odds of task success during both With-installation phases than during the Without-installation phase, although individual response patterns were heterogeneous. The proportion of children waiting successfully for 300 s was lowest during the Without-installation phase, but substantial individual variability was observed. Teacher ratings collected for a limited subset of children showed a broadly similar pattern.

CONCLUSIONS

Toddlers' IC-related performance differed across classroom periods with and without sound-absorbing materials. These findings provide preliminary field-based evidence that the classroom intervention may have modified multiple aspects of the classroom environment, including teachers' behaviors and teacher-child interactional processes, thereby contributing to variation in toddlers' IC-related performance. Future studies should determine the relative contributions of acoustic and non-acoustic pathways underlying these intervention-related changes.