There are some relevant follow-up studies, e.g.: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730121/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730121/ >

There are some relevant follow-up studies, e.g.: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730121/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730121/ > We demonstrated that children’s sustained decisions to wait for a greater reward rather than quickly taking a lesser reward are strongly influenced by the reliability of the environment (in this case, the reliability of the researcher’s verbal assurances). More broadly, we have shown that young children’s performance on delay-of-gratification tasks can be strongly influenced by an implicit rational decision-making process.