Ironically, the type of studies you're citing make the same mistake in not controlling for the effects of income. One reason that poor children are likely to "

Ironically, the type of studies you're citing make the same mistake in not controlling for the effects of income. One reason that poor children are likely to "fail" the marshmallow test is because growing up in poverty means that promises made to you are less likely to work out - so, having learned from experience, they make the rational choice. https://bigthink.com/mind-brain/new-marshmallow-experiment https://bigthink.com/mind-brain/new-marshmallow-experiment