Can people be selectively smart&stupid?

I hate math, so, naturally I was awful at it my entire life, I barely passed a few grades in middle and high school due to it, even though I had additional post-school classes of it. Same thing with chemistry and I think physics, basically all classes I really disliked.

On the other hand, I completely learned English by my year just by watching tv, despite not living anywhere near a English speaking country, more recently I also learned Russian in just 2 years and went from understanding 5-10% of dialogues in movies to 99,9% and being able to have complex conversations with Russians myself, a few years ago I learned the Greek alphabet in less than a week and I still remember it despite never really using it again, so I guess that I am somewhat good at languages, even though I don’t devote time to learning them, but learn them on the fly, but if I did devote time, I would be even better.

I can also remember a bunch of military, political and historical things no one else cares about, once we had a test in high school and I was interested in the topics of the (history) class and despite me being one of the laziest and worst students, I got an A, just by listening to the lecture, without studying, while a few of hardworking students got A- and B+, most of the class just got C’s, and it’s not just that specific test, I had the same thing happen a few times, basically if I’m interested in the topic, I get great grades even without learning the lecture, but if I am not interested in the topic, I can learn it for hours and days, but it won’t help.

I did several iq tests on the internet, which are of course not 100% correct, but nonetheless I usually got results like 100 to 110, which would make me pretty much average, so why do I have so much trouble learning things I dislike, but no trouble learning things I like?

Yes, you can be smart in some things and not so much in others. Multiple ways:

  1. someone can have specific learning disabilities (dyslexia, dyscalculia, etc.),
  2. there’s different kinds of intelligence. Geometry and grammar don’t use the same parts of the brain.
  3. and yes, being interested in something helps learn it. A huge difference between good and bad teachers is that the good ones are capable of keeping more students interested in the subject, or at least paying attention to it.

And very often people have a disconnect between different aspects of themselves, including an aspect which knows something and one with its fingers stuck in its ears. The pharmacist who, having a diagnosis of cancer, starts getting homeopathic treatments. His training says “that’s crap”; his fear says “any port in a storm”. My uncle could explain calmly that homeopathy was bollocks… for other people.

Learning math requires that previous steps be mastered before going on to the next step. Lots of other subjects don’t require this as much. If a person doesn’t grasp one of these steps (possibly due to bad instruction), they may conclude that they’re stupid. The problem can be corrected, but that requires recognizing the deficiency, and going back to master the previous step.

Also, the value of knowing math is less obvious than with many other subjects. (We learn a foreign language to talk to people who speak that language, but what use is algebra?) It’s hard to get motivated for a subject that seems confusing and useless.

That said, smart people can definitely have blind spots in reasoning, especially when emotions are involved.

Up until I got to the part where you said you’re not a native English speaker, but learned English on your own, it sounded like you were no different than the typical grade school/high school kid that dislikes and/or isn’t good with hard sciences, does just fine with Language Arts and hit or miss with Social Studies.
I don’t think there’s anything odd about that at all. For many people, for a variety of reasons, Science is difficult to grasp, and Math is just the hard parts of science boiled down into an ugodly boring class (personally, I always liked it).
I think it’s understandable that many people don’t like it and therefore don’t do well in it.
Lastly, and I doubt this is the case, one of the things you mentioned is a symptom of ADD. When I was trying to convince my parents that I had it and that treating it (with meds) may help my grades, often they’d fire back with something along the lines of “you don’t have an attention problem, you just don’t like [subject], when you find something you like, you don’t lift your head for hours.” One day I was reading something and learned that one of the symptoms of ADD is hyperfocus.
I’m sure (like with mine) many parents wrote off the possibility of their child having ADD and assumed they just ignored the parts of school they didn’t like when, in fact, they really just couldn’t do them.

Like I said, probably not the case. What you explained sounds like the typical school kid to me. Good at the things they like, not so good at the things they don’t like. Remember, those kids that were getting straight A’s the entire time you knew them (Kindergarten through HS), were likely busting their humps every day after school. Sure, they made it look easy and yeah, they’re doctors now, but who wants to be doing 4 or 5 hours of homework every night. Not me.

I cannot remember the study so no cite but my therapist daughter informs me that there are essentially two beliefs about learning and these are set at an early age. The first belief is that the you can learn anything if you work at it patiently. The other is that if something doesn’t come easily it’s because you’re stupid. Obviously, the first one is a lot more conducive to learning something that is rather difficult at least at first.

I am a great example of the second type of person. I have the best excuse though – many activities and skills which others find arduous or frustrating I have always found virtually effortless – anything to do with language, writing, and the arts, among other things. Conversely, everything to do with numbers and relationships of numbers I find absolutely impossible no matter how hard I try. I was an older adult before I found out that I have all the classic signs of dyscalculia – and I mean all of them. I was twelve before I could tell time on an analog clock, for example, and if I take three measurements in a row I will invariably forget what the first one was, and usually the second one as well. I literally can barely add and subtract. And I mean that literally.

However, most people are not like me, and the first strategy is going to work out a lot better for them than it ever has for me.

Here’s one relevant article (from The Atlantic): The Myth of ‘I’m Bad at Math’.

It’s not just about math, but about learning and intelligence in general, and the two conflicting beliefs that “You have a certain amount of intelligence, and you really can’t do much to change it” vs “You can always greatly change how intelligent you are.”

I know it’s not the case for everybody, but when it came to Physics and Chemistry one of the things we were taught was some of their history; the whole part about atomic models was a series of tales, of “and then soandso said ‘but what about this other thing? the model doesn’t explain it!’” and searching for a model which would explain that thing, again and again. Math? Many of the more-complicated parts were put in context by the P&C we were having at the same time; asking about context for those parts which didn’t get it from P&C would get answers which made it sound as if our attempts at finding utility in math corrupted this most sacred and ethereal of all fields of knowledge.

Many years later I realized that my teachers who did that were also those who least understood the subject. Like every other science, math’s biggest leaps came in great part from someone needing to do something and not having the tools for it; knowing those stories and those applications makes it both easier to get motivated and to visualize what the weird symbols are about (my primary language isn’t Spanish; it’s geometry. For people who can’t do geometry to save their life, the understanding will be different from mine).

I was terrible at high school algebra, but I aced geometry even though i slept through most of the classes. Some people are good at spacial recognition and bad at abstractions.