One could say that the ability to delay gratification - not to want everything right here and right now - is one of the hallmarks of becoming a mature, civilized human being, albeit one sadly missing from a lot of people. The inability to take the long-term view is sometimes thought to be one of the symptoms of attention-deficit hyperactivity disorder (ADHD) and a team of researchers from Oregon Health & Sciences University sought to test this theory in a study of 58 seven-to-nine-year-olds. The children were asked whether they wanted to receive a smaller sum of money straight away or a larger one at some point in the future. Once the effect of IQ was taken into account the children with ADHD were no more likely to opt for instant gratification than the children without it.
Wilson, Vanessa B. ... [et al] - Delay discounting of reward in ADHD: application in young children
Journal of Child Psychology and Psychiatry doi:10.1111/j.1469-7610.2010.02347.x