Expected IQ spread on a jury

There’s been some discussion online lately about how a large difference in IQ makes it difficult for two people to communicate. There have been studies that confirm this effect. The difficulty is not insurmountable, but it takes deliberate effort to overcome. Someone dismissed this communication difficulty by pointing out that the expected difference in IQ between two individuals is around 17, suggesting that most communication is between people who differ by more than one standard deviation in IQ. But this calculation assumes people are chosen at random, which they usually are not. People tend to live around and work around others of similar intelligence. However, a jury is a random sample. It’s not a perfect random sample. For one thing, it starts with a random sample of people who are registered to vote, or who have a drivers license, not all individuals. Furthermore, the pool of potential jurors is reduced to a jury through the process of voir dire, which is not random. For this…