- One Piece's Luffy,
- Naruto's Naruto,
- Fairy Tail's Natsu,
- Reborn's Tsuna,
- Dragon Ball's Goku
All of the above are shown to be simple-minded and foolish.
Why is it so common to depict the lead protagonist to be so stupid?
All of the above are shown to be simple-minded and foolish.
Why is it so common to depict the lead protagonist to be so stupid?
This is a common archetype in many forms of fiction, not just shounen anime and manga. for instance, many seinen romance series have protagonists who are usually at or below average intelligence, e.g. Clannad, Chobits, though seinen also has some intelligent protagonists like those from Death Note or Ghost in the Shell. Shoujo series also sometimes use this archetype. However, I suspect it is especially common in shounen series and other series targeted at children.
One reason for this is that if the protagonist frequently spends a lot of time deeply considering things, and comes up with complicated logical thinking to justify his actions, it can easily confuse some of the viewers, particularly younger children. In a mystery series, this might be acceptable, because the viewer is expecting to have to think critically to follow what's going on, but in an action series, it detracts from what most people are watching for.
Another reason is that for the protagonist to be a good hero (or arguably even a good antihero), they need to be identifiable to the average viewer. It's easy to identify with people who aren't as smart as you are, because at some point in your life you were like that. Since some of the viewers will be fairly young, to make this work you need to make the character at or below their intellectual level, which makes them appear really dumb considering their age. It's much harder to identify with someone who is far smarter than you. Extremely intelligent characters are supposed to be impressive rather than identifiable (e.g. Light and L from Death Note, who are identifiable in other ways, but not in terms of their intelligence). Of course, it's also possible to just make the character average intelligence and not put any emphasis on that direction (and lots of series do this), but shounen protagonists tend to be more like caricatures than real people, i.e. they have exaggerated features and characteristics, and intelligence is often one of them.
It's also worth noting that most shounen action shows were, at least originally, marketed to young boys. Most young boys are far more interested in being strong than in being smart. By making the character below-average intelligence, but unbelievably strong, it makes the character simultaneously identifiable and admirable.
There's also the comedy aspect. Almost all of these series involve comedy. For whatever reason, many people find people doing stupid things to be funny. A lot of these series exploit this by making the protagonist almost useless outside of battle. In the traditional Manzai style of comedy, they play the boke role, which is usually the more interesting role (hence fitting of the protagonist). That isn't to say that intelligent characters can't be comical, but it isn't as easily exploitable with little-to-no effort as it is if the protagonist is unintelligent.
Finally, the protagonists in most of these series are idealists. Intelligence, by and large, correlates with pragmatism, at least in anime. Pragmatic characters make good generals, but typically not interesting ones. To put it a different way, pragmatism wins wars, but idealism leads to epic battles, and in an action series that's what counts. Dragon Ball wouldn't be nearly as interesting if Goku resorted to some form of guerrilla tactics to win each battle, even though it might make things easier. The protagonist usually has some more level-headed allies who will pull out if they really are in a losing battle (e.g. Nami, Piccolo), but these characters aren't the ones you're supposed to identify with. Also, idealism is often portrayed as admirable in these series, which further adds to the character's good qualities.
There's also the aspect of tradition, as kuwaly's answer points out. So I think there are a lot of reasons why it works well to have an idiot hero in shounen action series, so it's understandable why they are common.
This seems to be a general feeling of creators for shounen, that characters should be straightforward and stupid. A lot of them also seem to have been based off of Dragonball
Regarding Naruto:
When creating Naruto, Masashi Kishimoto incorporated into the character a number of traits he felt made an ideal hero: a straightforward way of thinking, a mischievous side, and many of the attributes possessed by Son Gokū from the Dragon Ball franchise. He also made sure to keep Naruto "simple and stupid," since he does not like smart characters. Naruto himself is not modelled after anyone in particular, being conceived as childlike, with something of a dark side as a result of his harsh past. Despite this, he is always positive, making him unique in Kishimoto's eyes.
Regarding One Piece (it is worded slightly differently now, but this is where I originally got it from):
When drawing One Piece, Eiichiro Oda was heavily influenced by the manga Dragon Ball, and had the series in mind when designing his characters. Oda has said that when he was creating Luffy, he was thinking about "manliness", because Dragon Ball had already done all the things that a child could possibly be happy about.
Regarding Dragon Ball (also now worded slightly differently):
The Dragon Ball universe began as a loose adaptation of the classic Chinese novel Journey to the West, with Goku starting off as more or less a parody of Sun Wukong the Monkey King. Similarities between the two include Goku's prone for mischief as a child (due to his innocence), possession of Nyoibo (Sun Wukong's staff that can fill the entire universe), and Flying Nimbus (the magical cloud the Great Sage rode on in Journey to the West). As the Dragon Ball manga continued its run, he was able to develop differently, eventually turning out to have similar origins.
Shonen, for me, is all about doing the hard things. It's about effort, moving past self-doubt, facing impossible odds, and somehow through luck, faith, and grit you make it through. I think to do any and all of that instinctively, you have to be a little stupid.
I consider myself a smart person. Most of my friends are smart. My parents are smart. My brothers are smart. I think I know smart people. Smart people analyze things. They think about the odds, about their abilities, the utility of a certain action and do a rough calculation in their heads before they make decisions. In the real world, it's the right way to go. The trouble comes when you do too much analyzing and distance yourself from reality and hope.
Shonen heroes never do such a thing. They bulldoze their way past insecurity. They don't give it a second thought. All they know is that if they stick with it, if they keep punching, if they keep climbing, they will get where they want to go. Even if it's stupid. Even if it's impossible. They're insane or dumb. That's the only explanation. You can't just solve things by punching your enemies. You can't just keep running on a race track till your soles bleed or you collapse. You can't kneel for three days to make a point.
But they can.
And that's why it's so addictive. Because I want to believe that I can be like that. I want to be able to laugh off failure and keep trudging. I want to believe that the most important things in life are being a good friend, never giving up, and always following my own path, even when every rational indicator tells me to turn back or to hedge my bets.
Those protagonists aren’t dumb, but more so simple-minded. There are some definitions of the word that make it seem like simple-minded equals stupidity, but it honestly doesn’t mean stupid. People who are simple-minded can still problem solve pretty well even if it takes them longer to figure it out. They think and solve things simplistically, have simple ideologies, and have simplistic goals. That doesn’t make the characters stupid, their brains work a bit differently than the average person. They typically rely on their own strengths and abilities to make it through the day. They are in many ways seen as survivalists and are more practical than reasonable. This makes for very stubborn protagonists who don’t give up. For example, I kind of know someone who thinks this way, he can fix cars and trucks like it is second nature to him, and he’s done some insane fixes that other car mechanics find insane to attempt, and he just relies on what he has to solve these problem. Although he struggles in math and with solving puzzles. Like he absolutely hates puzzles because it takes a lot of brain power to solve stuff like that. That kind of problem solving isn’t their best ability. People believe that intelligence means you do well in school and make good grades. People who don’t do well in school are considered unintelligent. That isn’t the case. Intelligence comes in many forms and you can be intelligent in gathering and retaining knowledge but struggle with social or survival intelligence.
With that said, why does shounen have simple-minded characters. Well they are typically the easiest to develop and also provide good comedy to the anime. When you have characters that think simplistic than they usually struggle a lot in many areas. Later on you put other characters in those protagonists’ lives to build up those simplistic protagonists through influencing. Their struggles can be seen as relatable to most who struggle in their teenage or young adult life, but at the same time it is also suppose to make you feel better about yourself because you aren’t struggling as much as those kind of protagonists. I would argue though that there are plenty of shounen that have genius level protagonists and also a few that have average protagonists. However the ones you’ve listed do have that shounen troupe of the protagonists having simplistic thinking and problem solving.
I don’t know if you’ve watch Hunter X Hunter, but Gon has that same simple-minded protagonist troupe in this shounen anime. He thinks simplistically, but the writer does show that Gon can problem solve well and even better than the other characters during certain situations. He is shown to struggle with higher level concepts and explanations, but finds his own way around it or to understand those concepts. I don’t think anyone who watches the anime considers Gon stupid. There is an understand among those characters that Gon thinks differently than them, and the smarter characters in the anime are both fascinated with and sometimes make light humor of Gon’s thinking and how it affects his actions and judgements. Unlike the other animes like Naruto where all the characters call him stupid for struggling which makes them underestimate him. I’ve watched Naruto so much to know that he isn’t stupid and it is just that other character calling him that. It’s suppose to be humorous but it can give people like you the wrong idea about these protagonists. When people around those characters call them stupid, than that influences how you view those characters. It’s psychology, look up Asch Conformity Experiment on YouTube. It can help explain why you think these protagonists are stupid because the other characters consider them stupid and you believe them those characters to be right about the protagonists.
One of the reason for this is that we get attached to this type of personalities. Moreover, they sometimes make the viewers optimistic as the protagonists being stupid achieve many things which seems impossible!