Excerpts from Wikipedia:
A replication attempt with a sample from a more diverse population, over 10 times larger than the original study, showed only half the effect of the original study. The replication suggested that economic background, rather than willpower, explained the other half.
Work done in 2018 and 2024 found that the Marshmallow Test “does not reliably predict adult functioning”.
It’s great for a confirmation bias, but such a study is way too simplistic to really reach a conclusion. Oh, and:
The results seemed to indicate that not thinking about a reward enhances the ability to delay gratification, rather than focusing attention on the future reward.
Honestly, that’s not what I see from them. They may have the lowest paid employee working cashier, but the people who handle customer service desks are chosen and trained to handle these sort of situations diplomatically, even when effectively the same thing happens and they just talk bad about these clowns in the staff room. The only places I see people just openly admitting “I don’t care” attitude openly are usually people on a second hand market apps and people with small businesses who have their local market penned in. Might just be my experience, I’m also not in the US.