Smarter people tend to earn more money but also tend to spend more than less smart people.
Zagorsky's subjects earned an average of $234 to $616 more per year for each added IQ point, meaning someone with an IQ of 120 (top 10%) made $4,680 to $12,320 more than those crowded in the middle of the bell curve with an IQ of about 100. ...
Zagorsky adjusted for outside factors that affect wealth, such as education, divorce, inheritance, smoking and psychological well-being (yes, people with high self-esteem and a sense of control earn more) and, to his surprise, found:
* While those with above-average IQs were three times more likely to have a high income as those with below-average IQs, they were only 1.2 times more likely to have a high net worth. "Simply put, there are few individuals with below-average IQ scores who have high income, but there are relatively large numbers (of those with below-average IQs) who are wealthy," he wrote.
* No IQ group had built up "a significant financial cushion." The median baby boomer's wealth equaled 18.6 months of income, while the highest-scoring group, those with an IQ of 125 or above, had little more than two years of income saved.
* Subjects with a 105 IQ had the same median income as those with a 110 IQ but had a greater net worth: $83,918 compared with $71,445.
It seems likely to me that whatever mental threshold people set that determines how much they spend is independent of intelligence. If a person's brain says "stop spending, we've only got $x left" it doesn't really matter how fast the cash comes in, it goes out just as fast. Cash-flow is high, but net wealth hovers around $x.
Additionally, smart people might believe that their intelligence is an inexhaustible asset and that they can spend more money than an average person -- they're so smart, it will be easy to earn more!