The only research I can bring to bear on this question is my personal experience over many decades. It seems to me that what we call “moral integrity” is spread somewhat evenly across the entire spectrum of intelligence. Those who crack computer codes to hack into other people’s accounts or those, like Bernie Madoff, who scam others with ponzi schemes are often more intelligent than average. At the other end of the spectrum, we have people who overcharge when they do home repairs, taking short cuts on materials or on workmanship. These include small contractors and workers, many of whom may be below the median in intelligence.
I would guess that the smallest incidence of scam artists would come from the opposite ends of the intelligence spectrum. People who are intellectually challenged usually have a childlike innocence and honesty that renders them transparent and less prone to misrepresentation. Those who are intellectually gifted are usually so passionate about their cerebral pursuits that they are less interested in money and less likely to scam others. But even among this group there are a few scammers, such as the academics who plagiarize or attempt to steal from a colleague the credit for a scientific discovery.
The tendency to scam seems to be natural in the human animal as a means to gain advantage and could well be our default position. For example, researchers have revealed that monkeys, on discovering a cache of food, will hide the location from other members of their group and hoard it for themselves. It may be that we overcome this natural tendency through our family upbringing and our experience with the negative consequences of scamming. However, to avoid scamming in this response, I must admit that, except for the research with primates, the opinions expressed here are merely anecdotal and based on the limited scope of my observations.
