I thought working memory (WM) was mostly number of items recalled, and for most people it's 5-7. The actual test they used would benefit from exposure to video

I thought working memory (WM) was mostly number of items recalled, and for most people it's 5-7. The actual test they used would benefit from exposure to video games (poverty would affect access): > a screen that displayed one, two, or three dots for 2 s and instructed to remember where the dot(s) were located (Figure S2b). The screen then went blank (for 0.1 or 3 s), after which it changed color indicating that participants should touch the screen precisely where the dot(s) had appeared. Not a serious criticism, more about the nature of WM and how to measure it.