Honest question, and if there's any professionals who are in the know please comment.
I'm not fighter bashing, it's a sincere question. 
I don't think anyone here can say for sure. But I will say that if I was a betting man, I'd bet the house he's not developed past a 3rd grader. By no fault of his own, just saying.
He was abused when he was a kid and it hindered his development 
I've never met the man, but he has this really simple jack kinda look to him.
He came from absolute poverty w/ no education.
"Palhares is like a 12 years old kid. He was raised in a farm in Brazil, and you can’t picture a farm in Iowa. He’s so naive. The reality is, he has a completely different mindset. They’re born like Indians, and it’s like getting an Indian from the jungle and expect them to live here." - Renzo Gracie
Moist Gracie - In his post fight interview they asked him what happened and he said "Palhares do bad thing?"Lol
Early life and education
Palhares grew up in abject poverty in the Brazilian countryside. He recalls working in the fields to help support his family as young as age seven and said that there were times where there was not enough food for everyone. He eventually had to leave his shanty and move underneath a local bridge in a tent city slum. Palhares began training in Brazilian jiu-jitsu at the age of 15, before moving to Rio de Janeiro to compete professionally.[6]
He claimed the Fury Fighting Championship Middleweight Championship in December 2007 after defeating Flavio Mura, Pan-Am Jiu-Jitsu champion Fabio Negao, and Chute Boxe's Daniel Acacio in a tournament.
Palhares earned his Brazilian Jiu-Jitsu black belt under former UFC Middleweight Champion Murilo Bustamante and Bebeo Duarte. Experts in martial arts touted Palhares as one of the most naturally gifted grapplers today.[7]
Having spent his entire early career competing in Brazil, Palhares' first bout outside his home country was in the United States at UFC 84. He is considered to be one of the best in the world at leg locks, such as the heel hook and kneebar.[8] Palhares took 2nd place in the under 88 kg 2011 ADCC, finishing his first three opponents quickly with leg locks, before losing to established World Champion Andre Galvao in the final, by points.
Betwithme - He has a black belt... How dumb could he be?I know 2 purple belts that have mental disabilities. Sick guillotines too!
His childhood was fucking insane wasn't it? I think he turned out pretty normal, all things considered
I'd be surprised if he had an IQ above 70.
He did live in abject poverty. I remember one episode about him when he got into an accident and cut his chest. They literally stapled his skin together. That is what the huge scar is from.
He came from poverty and at times had to eat pig slop as a kid. It's a sad story.
MartialArtsMixed -Moist Gracie - In his post fight interview they asked him what happened and he said "Palhares do bad thing?"Lol
Then, he asked George if he could play with the rabbits.
Betwithme - He has a black belt... How dumb could he be?I'm not saying he has a mental issue, I don't think I'm qualified to make that judgement... but a lot of people with mental disorders are actually really skilled at what they're passionate about. Be it a sport, academic subject, martial art, video games, etc. I have a brother like that and I wrestled with someone like that in high school.
he is confused by doors
Moist Gracie - In his post fight interview they asked him what happened and he said "Palhares do bad thing?"That's one of the funniest things I've ever read. Lost it in bed reading this and woke my wife up
Moist Gracie - In his post fight interview they asked him what happened and he said "Palhares do bad thing?"
lol that's hilarious. vtfu
Moist Gracie - In his post fight interview they asked him what happened and he said "Palhares do bad thing?"That's fucking hilarious and so is your screen name. VU.
He's like a real-life Blanka. Didn't Bustamante kick him out of his camp b/c he kept injuring training partners or something?