Myth 1 — IQ is fixed at birth
Genetics influence cognitive ability, but they do not determine it. Identical twins raised apart end up with measurably different IQs. Education, nutrition, early language exposure, and even air quality have all been shown to shift scores by several points across populations.
Myth 2 — We use only 10% of our brain
Functional brain imaging shows that essentially every region of the brain has a known function and is active at some point during a normal day. The 10% myth has no scientific basis and almost certainly originated as a misquoted self-help slogan.
Myth 3 — IQ tests are culturally biased and useless
Older tests were criticised, fairly, for relying on vocabulary and references familiar mainly to one cultural group. Modern non-verbal tests like Raven's matrices were designed precisely to address this. Bias is real and worth scrutinising, but the entire field is not invalid.
Myth 4 — High-IQ people are all socially awkward
There is no measured correlation between high cognitive ability and poor social skill. The stereotype persists because outliers are memorable, not because they are representative.
Myth 5 — Brain games raise your IQ
As discussed elsewhere on this blog, commercial brain games mostly make you better at the games themselves. Real cognitive gains come from sleep, exercise, and genuinely difficult learning.
Myth 6 — Mensa-level IQ guarantees success
Long-term studies of high-IQ children show that they earn more on average than their peers, but life satisfaction depends far more on conscientiousness, social support, and luck than on raw cognitive horsepower.
Myth 7 — IQ peaks at 25 and declines from there
Different cognitive abilities peak at different ages. Processing speed does peak in the mid-twenties, but vocabulary and crystallised knowledge keep growing into the sixties. Wisdom — knowing which question to ask — improves for most of life.