What you just said sounds like a misunderstanding of the words "average" and "variance". Usually when things like intelligence is modeled, it is modeled as a no

What you just said sounds like a misunderstanding of the words "average" and "variance". Usually when things like intelligence is modeled, it is modeled as a normal distribution. Moving the average for a normal distribution moves the majority of people in the distribution. Variance just expresses how wide the distribution is, or how far you can expect people to deviate from the average. What you're saying seems to suggest the distribution is multimodal. I'm not sure that's what they said.