There are two different form of understandability that comes to my mind,
1. Things that you don't understand because you don't have the necessary background knowledge, 2. And the things you'd fundamentally never understand because of the limitations of your own mind, which is, limited by the IQ.
I' assuming you're trying to mean the second version here.
But still, I don't believe IQ alone can improve your reasoning capability, could it? Like with proper education, and knowledge, a person with average IQ would more likely be able to see the correct patterns, and connections between ideas, than a high IQ person without the required education would.
It's like - having the proper education, trumps the meaning of having a high IQ. But, it's true, given the similar environment, I'd assume, the high IQ person would do better.
Education is no substitute for IQ any more than IQ could be substituted for education. A high IQ individual has the potential to better utilize an education, all else being equal. Whether education or reasoning ability is more critical is very situational. In a tour guide, you definitely would prefer someone knowledgeable, in a detective you really want someone clever. At least for the moment the preferred workload distribution is generally for computers to help us with information retrieval and low level analysis which education trains us for while a human performs high level reasoning tasks which are represented by IQ.
I mean, if your goal is to get from point A to point B, having a fast car just means you go there faster.
I'm thinking of IQ in a similar way, as in - high IQ = faster car. But at the end of the day, it's still the same, isn't it? Please correct me if I'm wrong.