This might end up being one of the funniest scenes since watching my friend teach his grandma what email was. Both the directors and Marvel's president reference Captain America trying to figure out what a cellphone is, but the guarantee us that it won't make him look stupid like "fonduing" in The First Avenger or flying monkeys in The Avengers.
But he’s the most adaptive man on the planet. His brain’s been juiced, so he’s not going to be baffled for very long by your iPhone, so you have all those ideas first and then you’re like, “Those are stupid.”
~Christopher Markus, Writer of Captain America: The Winter Soldier
Cap's "blonde-moment" personality definitely defines him as a character, as well as his more definite moral compass compared to the rest of the Marvel characters defines his character so much, and makes him such a relatable person. This will both bring about some conflicts as well as some fun, uplifting comic relief.
You know, we’re careful not to make him a goofball fish out of water, you know. We don’t spend a lot of time with him trying to understand what an iPhone is. He’s, you know, if you took a 23-year-old – what do we calling Cap, I don’t know, 27? If you took a 27 year old and introduced him to something they’ve never seen before they’d probably figure it out. They wouldn’t be completely flummoxed. So we’re avoiding sort of the what is a cell phone. What is this magic glass that you type onto. We have some fun with it.
~Marvel Studios, President Kevin Feige
It's rather odd that iPhones would be referenced so many times by the people in charge of the movie, and I think their words explain why: they're trying to balance. Too much comedy makes the movie too much of a joke, but not enough and the dramatic moments just feel too forced. This possible iPhone scene was more than likely a source of debate over balance, and even if it's not in the film may turn up as a deleted scene. Though it's clear they won't sit Cap down and explain how phones work, it's clear Cap is going to do some memorably funny things when his curiosity gets the best of him.