Did the marshmallow test replicate? Not in the way it was reported.
A four-year-old's ability to delay gratification predicts their life outcomes.
Watts, Duncan & Quan (2018), a larger and more representative sample: the correlation shrank sharply once family background and early cognitive ability were controlled.
Check it yourself: doi.org/10.1177/0956797618761661
Delay of gratification is substantially a function of circumstance and of whether promises have been kept to you before. Build the environment, not the child's grit.
Every law on Useful Mind tells you how strong the evidence behind it is. The ones that failed are kept here rather than quietly deleted, because knowing which advice is wrong saves you as much as knowing which is right.
See the ones that held up