This phenomenan is especially notable nowadays where wealthy parents canb buy a diagnosis to givetheir children extra time on IQ tests.
And then of course ADHD drugs and other stimulants raise the question of what it means for a person to "have" an IQ, if that IQ (and/or test score) is influenced by doping. Stimulants and the brain question our notion of what is an "individual", much as the bacteria in our gut do. The idea of an "individual" is a very synthetic Western mathematical concept that does not have a strong basis in the science of the natural world.
https://www.sciencealert.com/this-tree-stump-is-mysteriously... "Scientists Find Weird, Zombie-Like Tree Being Kept Alive by a Forest 'Superorganism'"
[1] https://www.jstor.org/stable/2294274?seq=1#page_scan_tab_con...