[Retric]

IQ tests are proxies for intelegence but not direct measurements. They are fairly good at that from around 60-140, and less useful at the top and bottom.

As to low IQ scores people with an IQ of 60 generally don't have anything that they preform very well. The problem is everything we think of as takes even something as simple as holding your hand steady is really complicated. Getting better at even simple motor functions takes feedback loops, effort, and optimization. Further, intelegence generally allows people to optimize more quickly even as an infant. Which means intelegent people not only get to optimize more quickly they have more time to optimize complex tasks or tasks they are worse at.

Specialization of course kicks in, but the sills a six year old has are fairly universal and things 98% of people can do. Intelegent people tend to be better at.

[CuriouslyC]

An IQ of 60 isn't difference, it's indicative of either malnutrition, severe neglect, or some form of developmental disorder. In fact, I'd be surprised if there are many people of below average intelligence that don't suffer from one of those things. I'd even wager that if you took any random infant that didn't have a developmental problem and raised them in a loving affluent western family with good food and an enriched environment odds are good their IQ would measure >110 after a few years.

[Retric]

That's your own bias talking, genetics and environmental toxins can both cause significant issues. But, so can non genetic birth defects resulting from disease or what amounts to bad luck.

Further sub 110 IQ's don't indicate a problem. Natural variation is simply much wider than you assume.