Study claims that shorter people may be less intelligent than their taller counterparts
As a short person (5'2, to be precise), I have encountered numerous difficulties throughout my life. As a kid, I was always the one left out from riding the rollercoasters at theme parks; as a teen, I was constantly reassured that I was just "a late bloomer", and now, as an adult, I still find myself climbing onto the kitchen counter to reach my cereal every morning.
But, aside from always ending up standing in someone's armpit on the train or having to stand on tiptoes every time I want to hug a member of my (annoyingly quite tall) family, there aren't too many downsides to being little. At least, that's what I thought.
As it turns out, however, there might be one other tiny negative factor about being small: it could mean you're not as smart as taller people.
According to a study published in Behavior Genetics in 2014, there is a positive correlation between greater height and higher intelligence.
As the study explains, "Evidence from observational studies suggests that better cognitive performance (as assessed by IQ-type tests) is associated with better health outcomes and lower mortality risk." Likewise, "Greater height is also associated with a lower risk of a series of health outcomes including coronary heart disease, stroke, accidents and suicide."
So, if being smarter is associated with better health, and being taller is also linked to better health, there should be a link between being smart and being tall - right?
In order to test this hypothesis, researchers studied over 24,000 participants between the ages of 35 and 65 across a five-year span.
"General intelligence was assessed by extracting the first, unrotated principal component from four cognitive tests that measured processing speed, verbal declarative memory, executive function, and vocabulary," the study says. "Height was measured during clinical examination by asking each participant to remove their shoes and to stand as erectly as possible with their back and shoulders against the freestanding measurement device."
After adjusting for factors such as gender and age, the scientists analysed the results. And this is what they discovered:
"In this study we found a moderate and statistically significant genetic correlation between height and general intelligence." However, they then went on to say: "Whereas the phenotypic correlation between these measures was small (~0.16), the bulk of this correlation can be explained by common additive genetic variants, and variants in linkage disequilibrium with them."
"The reason for the intelligence-health relation is not fully understood," the study concludes.
"One of several non-exclusive possibilities is that height and intelligence are both markers of ‘system integrity’. The present phenotypic and genetic correlation between them provides partial support for that suggestion. Further research should examine whether their shared genetic variation is associated with health outcomes, and seek to identify the molecular mechanisms.
"In conclusion, we found a moderate molecular genetic correlation between height and intelligence. Furthermore, the majority of the phenotypic correlation between the traits can be explained by shared genetic influences."
Basically, then being tall doesn't make you smart (just as being short doesn't make you dumb), but the genes associated with greater height are also associated with greater intelligence. There's a correlation, but not necessarily causation - so don't get too smug, tall folks.
Oh, and shorter people, remember this: great things come in small packages... even if those packages need help reaching the top shelf in the supermarket!