Developmental gains at age 0-2 mirror Flynn IQ rises. This rules out test-taking effect, education, etc. as causes and suggests better nutrition.
A high correlation was found between increased developmental gains in recent years and the Flynn Effect. In other words, the FE is already operating from ages 0-2. That is too early for education or many other environmental effects to take place and the only reasonable explanation for Flynn-like gains at such a very early age is better nutrition. Furthermore, education is ruled out as is test-taking or practice effects, as infants don’t practice taking tests. Better test-taking skills has been suggested as a reason for the FE, but there seems to be a lot of good evidence that this is not true. Furthermore, infants get no formal education, so education cannot be a possible source of these early gains.
Also the theory that the Flynn Effect represents “hollow gains” and not any real increase in intelligence is laid to rest here. Developmental gains means that children are reaching real developmental milestones faster and better than they were before. The only way that could possibly be interpreted is as an intelligence increase. It’s not a “hollow gain” to for an infant to reach developmental milestones faster and better than they did earlier. If children are reaching these milestones better and sooner than they were before, that can only be possible if they are definitely smarter.
I always thought there was nothing to this “hollow gains” nonsense, and this is more evidence of that.
Conclusion: The Flynn Effect is real and appears to represent an actual intelligence increase, possibly related to better nutrition. It seems reasonable that better nutrition would make better brains, and that may be what is occurring.