Originally Posted by Val
I'm going to speculate that working memory, processing speed, etc., may peak sooner in people with lower IQs and later in people with higher IQs. I have little evidence for this statement

FWIW, although not recent, Val's hunch brought to mind this about gifted brain development and EF: http://www.nimh.nih.gov/news/science-news/2006/cortex-matures-faster-in-youth-with-highest-iq.shtml (also discussed here: http://blogs.edweek.org/teachers/unwrapping_the_gifted/2010/02/what_brain_imaging_shows_us_ab.html).