In the Avengers movie,

Bruce Banner came to Manhattan on a motorbike after the portal had been opened. Moments later, Iron Man arrived followed by a big alien ship. Bruce Banner started to move towards that coming ship.

I thought Dr. Banner would become the Hulk during his collision, but he became the Hulk just before the collision when he was not angry (or, similar emotion). How?

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    In addition to the psychiatric assessment I offered below (Anger Management, etc - basing my answer on contemporary psychological descriptions), I would like to also offer that the "counter" described, as in "Days Without Incident," is extremely parallel to the way addicts (alchohol, narcotics) enrolled in AA or NA (alcoholics anonymous, narcotics anonymous) also keep a very strict total of "Days Without A Drink /Drugs." Its a clear measure of success and self-discipline vis-a-vis a very tough reality they are trying to change and ultimately overcome. More info: see my entry below.
    – AJotr
    May 18, 2012 at 21:34
  • From The Incredible Hulk it seems that not just anger, but an elevated pulse rate in general seems to trigger his transformation. If that's the case, then he need not be actually be angry to transform. He can simply trigger a transformation by speeding up his pulse alone, which to be honest, is a fairly simple thing to do.
    – Stark07
    Apr 25, 2014 at 7:29

14 Answers 14


The basic premise of Hulk is that when Bruce Banner becomes angry, harmed, or life is in danger, he turns into the Hulk. At the end of the Incredible Hulk (2008), it is shown that Bruce can willfully turn into the Hulk.

The scene below we see Dr. Banner meditating, at peace.

Bruce meditating

Soon after, his eyes turn green. He's starting to turn into the Hulk. This shows that he doesn't have to be physically harmed to turn, he can control it.

Bruce beginning to turn into the Hulk

In the Avengers movie, during the scene mentioned, Captain America says:

"Doc... I think now is the perfect time for you to get angry."

Bruce Banner responds:

"That's my secret Cap, I'm always angry."

I don't believe it was meant literally. It's more of a jest or catchphrase before doing something incredible. But the meaning behind it is that he can turn at will, which from the previous 2008 Hulk movie, he trained himself to do.

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    @SachinShekhar: I can't agree. I feel that was the point of the movie. At the start he's running away from the Hulk, using meditation as a way to block it out. At the end he's learned to accept that the Hulk won't hurt innocents, only defend itself when provoked - he doesn't like it, but he trusts it more, as Betty does. Yes, he's learning to control it, but that's instead of denying it - changing when he wants to, on his terms.
    – Tynam
    May 11, 2012 at 7:58
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    @SachinShekhar Can you explain then why they have a counter for Days without Incident then?
    – spong
    May 11, 2012 at 7:59
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    @SachinShekhar I think there is a very specific reason why he's turning, because he wants to. He's far out in a forest, away from everyone, alone, and meditating. There's nothing to make him angry or harm him. This is so in case if he can't control it, no one is nearby to get hurt. I think his eyes turning green is exactly that, he's controlling his breathing and heartbeat, in control of the Hulk.
    – spong
    May 11, 2012 at 8:17
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    "That's my secret Cap, I'm always angry." to me is the pivotal point. He has learned to control his anger, but he is still angry (as he should, if he loses his temper, he turns into the Hulk, something he never asked for). All he has to do is to stop suppressing his anger and he becomes the Hulk.
    – Martijn
    May 11, 2012 at 13:53
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    My wife pointed something out: the movies show an out-of-control Hulk when Banner changes involuntarily due to anger, but when Banner changes to the Hulk on purpose, the Hulk is much more controlled (willing to take orders from Cap, for example). Probably best to keep the orders simple, though (like, "And Hulk? ...Smash.") BTW my wife isn't at all a comics or SF geek like me, so kudos to Joss Whedon for making a movie that engaged her interest.
    – steveha
    Feb 28, 2014 at 23:30

No offense but I disagree with Sunpech's analysis that Banner was joking when he said "I am always angry." In the realm of psychology there are symptoms in perfectly ordinary people of increased adrenalin, i.e. adrenalin barely above normal range. The effect of this can very easily lead to a kind of "contained rage syndrome" where the individual tends to feel oddly "angry" and irritable without any necessary outside stimulus to make them feel this way. We are talking a truly microscopic amount of increased adrenalin as the substance is in fact insanely potent and powerful, which is why the human body has so many mechanisms for CLEARING adrenalin from the blood stream as fast as possible when it is even the tiniest bit above normal. One sees similar symptoms in cases of a very slight-but-constant increase in testosterone (the famous "roid rage") and also in very down to earth cases of too much exposure to a constant high-stress environment (commonly leading to hypertension and high blood pressure).

Consider that Banner's chemical change is that his body goes from just-above-normal to insanely off-the-chart huge amounts of adrenalin in milliseconds (as adrenalin works that fast, and any stressful environment can cause release, e.g. getting bonked on the head when the heli-carrier propeller exploded in AVENGERS). Once the adrenal release begins, the trouble is stopping it, so consider that Banner's physiology got messed up and the normal pathways to clear the adrenalin do not function properly for hours at a time, leaving him full of this catalyst for the big green change.

Cross-referencing this with a typical study of Anger Management (which includes meditation at times) and you get a picture of someone very much like us who constantly has just the tiniest drop too much adrenalin coursing through their blood At All Times. The feeling of "Being Angry" would be a perpetual battle for their rational mind to abate and transform by way of self-control to a calmer, less angry state via standard Anger Management techniques which numerous Hulk references say Banner requires to stay Banner. Thus he is always on the edge, and all he has to do is take the smallest millisecond to STOP trying to control that anger and WHAM - Hulk.

ADD to this Banner's comment that "it's like being a giant exposed nerve" and you get the sense that - also an occurrence of adrenal release and sympathetic nervous system arousal in perfectly ordinary humans - he is in a state of hyper-sensitivity, which in his human form means he has to work hard to concentrate. People who have this condition also often develop varying degrees of OCD, which can very well manifest into pouring oneself into a mind-absorbing world like Science, especially if one is already a scientific genius. Thus Banner's obsession with Science is one of the ways he cope's, handles all the input coming in through his hyper-aroused senses, and stays calm.
Really all he has to do is stop all this work at staying calm for one split second and the Hulk chemistry takes over. Thus his comment, "I am always angry" (subtext - "but I spend all my energy keeping that anger contained.")

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    I'm open for to others disagreeing with me and other interpretations, but please format the answer to address the question asked. Or you can start a brand new question asking if this popular quote from the movie was meant literally, and give your extended answer there.
    – spong
    May 15, 2012 at 4:41
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    +1, this makes a lot more sense than the accepted answer, and is more consistent with what we see and hear him say.
    – Izkata
    May 15, 2012 at 10:45
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    @ Izkata - thank you. Please hit the +1 on my reply as "someone" disliked what I wrote so your +1 would be nice. @ sunpech - please explain how in any way my answer was not 100% a direct and logical reply to the exact question asked...???
    – AJotr
    May 17, 2012 at 2:42
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    +1 - this is exactly the way that I saw it. You could even see it in other scenes, which is why in my estimation Mark Ruffalo has played the best Banner to date. You can't act the Hulk - the pathos has to come through Banner and he nailed it.
    – Chuck Dee
    Nov 9, 2012 at 2:14
  • I didn't upvote spong's otherwise good answer specifically because of that bit about it being a joke. Thanks for the better answer.
    – DCShannon
    Feb 25, 2016 at 6:29

"That is my secret captain, I'm always angry"

That is what he said in the movie.


When Mark Ruffalo uttered the phrase

That's my secret Cap, I'm always angry

in the Avengers movie, it was as revolutionary a synthesis for the character as was his initial subjection to gamma radiation.

The idea fundamentally changed how we view the Hulk. Since his inception, we have always assumed that the Hulk was the creation and Banner its creator. Equally implied is that the term of alter ego was attached, singularly, to the Hulk. This single uttered line turns that notion on its head. It is Banner that is, in fact, the alter ego. Banner is not controlling the Hulk so much as the Hulk is trying to have himself controlled by Banner. In other words Banner (post gamma incident) is now essentially the Hulk. Banner is a skin he dons to protect his psyche (as his body, obviously, needs no protecting) from society, or if you prefer, protect society from himself.

This notion seemed all but ratified when Ruffalo, earlier on in the movie, informed the others of his attempt at suicide which resulted in "the other guy" simply spitting the bullet out. It is not that Banner has that amount of control over the Hulk, so much as, the Hulk simply reverted to his natural form to protect himself from a bullet to the brain.


Throughout the film he has tiny little outbursts of anger. He has learned to live angry. It's like alcohol tolerance. The more you drink on a regular basis the higher your tolerance goes up. So having 5 beers a night for a few months will eventually result in that five beers having no effect on you. So then you go to 7 beers, continuously climbing. My thinking is that he truly is always angry, but never to a point that'd be dangerous. He keeps himself angry near his breaking point so he can use that built up rage whenever he needs it to change. That being the case, being near boiling point at all times also made it easier to control the Hulk while transformed. Punching Thor shows that he doesn't have 100% control though, but close enough.

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    I'm not sure that punching Thor shows he doesn't have 100% control - given Hulk's power (and Thor's near perfect invulnerability), that little jab was more of a love tap.
    – Bevan
    Jul 2, 2012 at 21:08

Well actually, the way the transformation into the Hulk is described is first required in order to understand how this is willfully done.

The process by which Banner usually transforms into the Hulk is presumably the result of the chemical catalyst, adrenaline (a.k.a. epinephrine). As in normal human beings, Banner's adrenal medulla secretes large amounts of adrenaline in time of fear, rage, or stress, which hormonally stimulates the heart rate, increases blood-sugar levels, and inhibits sensations of fatigue. Whereas the secretion heightens normal physical abilities in normal human beings, in Banner's case it triggers the complex chemical-extra-physical process that transforms him into the Hulk. The total time of transformation falls anywhere between seconds to five minutes, depending on the initial adrenaline surge, which will be determined by the original stimulus. Soon after the transformation, the amount of adrenalin in the Hulk will return to more normal, reduced levels. However, there have been instances in which Banner became the Hulk without any discernible increase in heart rate or adrenal levels, suggesting that the true trigger mechanism into the Hulk is far more psychological than physical"

-Marvel Wiki

In the 2008 Incredible Hulk movie, Banner is learning to control his breathing. Breathing and heart rate are connected. Your heart and lungs work in tandem. Presumably, if this effect is physical, he simply controls his breathing to increase his heart rate and quickly boost his adrenaline in order to transform.

If this is psychological, you have to look at the fact that the Hulk is an entity. The Hulk is a part of Banner's psyche which, according to the canon comic universe, is shattered due to a form of Dissociative Identity Disorder. Each part of Hulk is one of these identities. For example, the Savage Hulk, or the Hulk most people are familiar with represents Banner's anger. Banner himself is the emotionally repressed core state. Another example completely from the comics is "The Beast" which represented Banner's guilt, the mindless Hulk which was what Banner would fear the Hulk would become etc. etc.

So, presumably in his time meditating on the Hulk, he either became aware of the fact that Savage Hulk is an entity, and came to an agreement with him, thus being technically "always angry", or realized he can channel the Hulk's desire to simply be "left alone".


He didn't learn to control the hulk. With meditation he learned to suppress his anger in the Edward Norton Hulk film, taught to him by his instructor. In avengers he showed what he learn from that instructor that through meditation and practice he can control his anger through any situation. Then he choose to let it out at will. Kinda like holding feelings inside then lashing out when you choose.


Consider what Bruce Banner does when he's not Hulking. He is out helping the weak and vulnerable, those abandoned by others who could be helping. He lives among them and puts his brilliance to work for them.

He is angry for many reasons. Truly angry. All of the time. But not just about the condition that fate gave him. He's angry about the condition of the weak and vulnerable caused by greed, corruption and mindlessness.

All of the time.

  • I like your sentiment, but I do not see any supporting evidence for this answer.
    – kzh
    Jul 25, 2013 at 0:44

The Hulk can change at will. If you go back the the 2008 version with Ed Norton, he started out only changing when angry or threatened. Once the scientist(Mr. Blue) who was transformed in the villain know as The Leader tried to cure Banner with his gamma treatment, it altered Banner's genetics to where he could control his transformation at will. He still changes automatically as a means of preservation which is why Banner stated in the Hulk 2012 that when he tried to shoot himself in the mouth his alter ego the Hulk spit out the bullet. Sunpech is 100% correct! Banner can change at will, however his alter ego the Hulk will automatically come out if either are threatened. This is in line with the comic book with the exception that in the comic book, his exposure to the radiation that gives him this control comes from radioactive meteor storm when he was returning to earth after being sent into space as the Grey Hulk.


Ok. it took me a while but I got this (i haven't been thinking about it since April. I lived my life and stuff...)

We think Banner is himself 90% of the time and turns into Hulk when he's angry (hurts himself changing a tyre, stuck in traffic). He's not. He's angry 100% of the time (at his situation, even suicidal per the film). Why isn't he Hulk 100% of the time? He's suppressing it. Yoga etc per end of the Ed Norton film.

He can turn into the Hulk at will, because he stops trying to suppress it. He's always angry.


Excellent answers!

But of all the answers here, the one I have to agree with most was the one with the lowest positive score. Smartdread's.

The Hulk is not a chemical reaction. He is not summoned by adrenaline. Nor is he controlled.

Think of the Hulk as an emotion elemental, composed entirely of negative emotions and driven completely by them. This actually is supported by the canon, and I will explain at the end of this post.

Bruce Banner has always had seriously repressed emotions, and these emotions ARE the Hulk. The Hulk hates Banner for being weak, powerless, useless.. and Banner hates Banner for the same reason. Furthermore, ALL negative feelings are embodied in the Hulk. Fear of death makes the Hulk essentially unkillable. Fear of any entity makes the Hulk crush it. And this very same fear causes the Hulk to RAGE for being weak enough to feel it.

Now, the Hulk exists inside Banner. Raging. But he is as much as separate entity as he is part of Banner. He REPRESENTS the frustration, fear and anger Banner feels, which is further increased by Banner's inability to control him, and fear of the very emotions which he has to bottle.

Put short, the Hulk is not an adrenaline reaction. He is a self propogating, self insisting being, and also, essentially, living, sentient emotion. Banner doesn't CONTROL him so much as LET HIM GO. He cannot change back if the Hulk doesn't let him, or get smashed the hell up.

Now, I'd like to explain something.

• The Hulk can see astral beings, as demonstrated by his once seeing Dr. Strange's astral form.

• The Hulk cannot be mind controlled for long, by anyone.

• Telepathy, and mind-control, which is a subset of telepathy, are accomplished through, or with energies from, or similar to, the Astral Plane. (this is why all powerful telepaths can manifest an "Astral Form" which is their representation on the Astral Plane).

• The Astral Plane is the source of the Power Cosmic (as stated by the Silver Surfer).

• One aspect of the Power Cosmic and its abilities is transmutation and matter generation, as used by Galactus and the Silver Surfer.

• The Hulk has returned from the Astral plane and several other planes by sheer force of will, and fist.

I propose that the Hulk is a fully formed, concrete, Astral projection, connected to, and manifested by, Bruce Banner's processing of gamma radiation. This is why Banner is always angry, as the Hulk, technically a fragment of Banner's Astral form, is also a fully formed personality composed of rage and feelings of weakness and self-defense.

When the gamma radiation is drained out of Banner quickly enough, it becomes almost impossible for him to manifest the Hulk, as he cannot generate the conditions to pull the Hulk from the Astral plane. Conversely, once the Hulk is angry enough, and has been angry for long enough, he processes so much Power Cosmic (Astral Energy) that he begins to GENERATE GAMMA RADIATION, the very energy he uses to link to the Astral Plane, solidifying the connection.

This explains all the Hulk's gain in mass, invulnerability, regeneration and mutation.

However, it does bring up another question. If I'm correct, doesn't that mean Bruce Banner is a mutant with the ability to metabolize high energy electromagnetic radiation to create a connection to the Astral Plane? He's a portal?


He probably turns into the Hulk at will by tapping into his own negative feelings (stemming things like childhood abuse and trauma) e.g. anger he's suppressed and kept within him for all those years. Along with meditation and anti-anxiety methods, you have a far more controlled Hulk and a valuable teammate to the Avengers.


you are all missing the point behind his words...""THATS MY SECRET"". He might have learned to control his anger. He might not. Its irrelevant to simple fact he does not disclose the true purpose of his ability. Don't overlook the simplicity of hos awesome nature. It is a condition he learned to live with the same way that any of us learns to live with things that we don't like. Just accept his awesome power and do not think to understand that he is God like. You do not question God and his intentions or power. Hulk is true power that is unstoppable, still suppressable, but amazing. Settle for that.


To put it in simpler terms for normal humans to understand; Imagine yourself taking a laxative and then trying as hard as you can to contain the inevitable. Remaining Banner requires all of his energy and focus. Turning into The Hulk is a release!

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