Anthropology: the study of human language, culture, societies, biological and material remains; study of human behavior and societies in the past and present

He's twitchy. Bruce notices this right away, but he's certain everyone notices. It's not exactly something the billionaire tries to hide. Bruce isn't even sure Tony knows just how twitchy he is. It's a natural thing almost, and if Tony is actually playing at being so fidgety, then he's very very good at it.

But that's beside the point. It doesn't matter. Bruce just notices it, so he thinks it's worth thinking about every so often. There has to be a reason that someone is as twitchy as this guy is.

Nevertheless…

Tony is also a deep thinker, a quick thinker, and a scattered thinker. It's strange to find such a combination in one person, but Bruce can't deny what he sees and hears. The man also has an uncanny ability to pick things up in a very short amount of time.

Things as complicated as thermonuclear astrophysics (Bruce didn't even know that was a thing at the time…) and things even more complicated such as people. The second is admittedly harder than the first and while Bruce will heartily agree that Tony is crap at communication and is sorely lacking in the tact department, he will vehemently affirm the man's skill in understanding another person. It's not exactly empathy, because the man is horribly selective in the people whose feelings he actually decides to care about and relate to.

It's close, though. Tony gets people.

It had taken only a matter of hours for the man to decide that poking Bruce with a sharp lab instrument wouldn't get him killed. Bruce hadn't been sure what to do with that, he'd been so caught off guard (though his first thought had been: friend). And it had only been after the whole New York incident that Cap had told him that of the five of them, Tony had been the only one that thought Bruce would show up.

Bruce isn't used to being understood so easily.

He watches Tony from across their shared lab space as he taps a pencil on a scribble-laden notepad. The engineer prefers holograms and computer jargon to lead and paper. Bruce is the old-fashioned one. Right now, Tony has a pencil between his teeth while five fingers fly over his custom-made keyboard and the other five are clenched semi-tightly around a coffee mug. Bruce frowns. "Tony?"

The man blinks, seeming to snap out of something. Dark eyes focus through the hologram and narrow in on Bruce's face. "Hm?"

"Why me?"

Now Tony is frowning. The coffee mug ends up on the desk top and the pencil is taken from his mouth. Of course the other fingers remain on the keyboard, and if they occasionally move distractedly, Bruce pays them no mind, because whatever it is they're doing, it isn't absentmindedness on Tony's part. He's used to the other man continuing to work while he simultaneously holds a conversation. "Why you what?"

"Why do you trust me?"

The frown is replaced with a knowing smirk. "Mutual understanding."

"What?"

"We're both mad scientists, Bruce. Emphasis on the mad part." Tony's eyes shift back to his work. "Unlike most people, you don't freak and run away."

It takes a moment, but then Bruce understands what Tony is saying. He's… oddly touched. They fall back into their work in mutual silent agreement that the topic will not be discussed in the future. Bruce is not used to being understood so easily and while he knows that he doesn't have the slightest clue as to what goes on in the other man's head, he can appreciate the fact that Tony appreciates him staying in spite of not knowing.

Perhaps eventually he'll tell his friend exactly what and who the Hulk is and how he functions. Knowing Tony, though, the man probably already has some fairly accurate guesses. And yet…

Tony stays too.