he DOES act differently, sometimes quite significantly so, but i think that's because he's kind of 'playing into' the 'character' of the alien. >>playing Hero
i think that that is what >>102484751
is misinterpreting as an actual physiological change. barring characters like jury rigg and wildmutt and rath where there is a clear change, ben is usually trying to play a character when he's going hero.
when hes four-arms, he understands that he looks like a tough guy, so he ought to act the part. when he's ditto he knows he's REALLY fucking irritating because there's like twelve of him at once, so he acts the part. when he's ghost freak he's more snide and freaky because he knows that he's a scary ghost and so he acts like it.
this often results in moments of him 'breaking character'. this usually happens when:
he thinks nobody is looking (like greymatter and counting jellybeans, upchuck trying to eat human food for the first time)
when he is genuinely caught off guard (when he was first cannonbolt and was trying to figure out what to do), or when he has no idea what the fuck he should act like (what the fuck should an upgrade act like? he has no idea)