There’s no generally right answer, but I don’t think challenge vs. respect is the right model to be using here. Indeed, I feel that the correct response to declarative claims in a given situation usually has nothing to do with the factual correctness of the claim.
Specifically, there are three things that could be going on here. The first is that your friend is making a status play: they’re being declarative because they want to assert that they or their tribe have special knowledge, or (rarely) because they want to prove they’re cool enough to get you to say that 2+2=5. Usually it’s a way of passively elevating the speaker rather than challenging another person; I’ve found that geeks in particular are liable to interpret surprising claims as challenges, though, because geek self-esteem is often bound up in being the smartest person in the room. This is often a social blunder; actively debating in this case is challenging your friend’s status, which is sometimes a good idea but usually isn’t.
The second option is that they’re making conversation. In this case they don’t care too much about the factual content of what they’re saying, but social rules differ on how you’re expected to respond. Some cultures like gentle, friendly debate; some expect you to graciously accept the information and discard it as irrelevant once you’re out of earshot; almost none prefer strenuous disagreement. Debate in this case is not a challenge, but will only be treated as a sign of respect if social conventions allow it. This is probably the most common option.
The final option is that your friend’s thinking out loud or trying to solve a problem, i.e. they actually care about factual correctness. This is when it becomes appropriate to fall back on serious questioning if you doubt the information being imparted, although you might have to couch it in more or less rhetorical gingerbread depending on relative status and local social norms. It’s also pretty rare.
There’s no generally right answer, but I don’t think challenge vs. respect is the right model to be using here. Indeed, I feel that the correct response to declarative claims in a given situation usually has nothing to do with the factual correctness of the claim.
Specifically, there are three things that could be going on here. The first is that your friend is making a status play: they’re being declarative because they want to assert that they or their tribe have special knowledge, or (rarely) because they want to prove they’re cool enough to get you to say that 2+2=5. Usually it’s a way of passively elevating the speaker rather than challenging another person; I’ve found that geeks in particular are liable to interpret surprising claims as challenges, though, because geek self-esteem is often bound up in being the smartest person in the room. This is often a social blunder; actively debating in this case is challenging your friend’s status, which is sometimes a good idea but usually isn’t.
The second option is that they’re making conversation. In this case they don’t care too much about the factual content of what they’re saying, but social rules differ on how you’re expected to respond. Some cultures like gentle, friendly debate; some expect you to graciously accept the information and discard it as irrelevant once you’re out of earshot; almost none prefer strenuous disagreement. Debate in this case is not a challenge, but will only be treated as a sign of respect if social conventions allow it. This is probably the most common option.
The final option is that your friend’s thinking out loud or trying to solve a problem, i.e. they actually care about factual correctness. This is when it becomes appropriate to fall back on serious questioning if you doubt the information being imparted, although you might have to couch it in more or less rhetorical gingerbread depending on relative status and local social norms. It’s also pretty rare.