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Article History

Received: 3 November 2024

Accepted: 13 November 2025

First Online: 29 January 2026

Competing interests

: The authors declare no competing interests.

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee of the Shanghai Normal University (Approval No: 20150602), dated 2 June 2015. Informed consent was obtained from all participants prior to their involvement in the study, in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

: Informed consent was obtained in September 2015 through homeroom teachers at public kindergartens in Shanghai, which serve children within their designated catchment areas. Teachers distributed printed consent forms to parents or legal guardians, who were given one week to review and return the signed documents. The forms clearly outlined the study’s purpose, procedures, use of anonymized data, and the voluntary nature of participation—including the right to withdraw at any time without consequence. Parents were informed that they would be asked to complete questionnaires at three time points and that data would be used solely for research purposes, including potential academic publication. Given that children constitute a vulnerable population, written consent was provided by guardians, and child assent was obtained in an age-appropriate manner through verbal explanations by teachers to ensure understanding and agreement. The entire process adhered to principles of legitimacy, respect, voluntariness, and transparency.