[logicallee]

Albert speaks first because he's Albert! They're obviously just going alphabetically.

Maybe my other comment was right and they should have been called Alice, Bob, and Carol.

The way I read the question, it's as though a moderator said: "Albert, tell me what's on your mind." "Bernard?" "Albert?"

I will add that #4 should certainly be in the past tense ("at first I didn't know") because this way Albert and Bernard are in on the fact that they're part of a logical puzzle!! They should not know that they are characters in a puzzle.

This is how I read the puzzle:

Moderator to Albert: tell the reader what you know.

Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too.

Moderator to Bernard: And you, Bernard?

Bernard: At first in this puzzle I don't know when Cheryl's birthday is (before Albert spoke), but now that you have asked Albert, and I've heard his response, I've figured it out.

Moderator to Albert: And any thoughts from you, now that Bernard has figured it out?

Albert: Yes. Given the information Bernard has now stated, I would say I also know Cheryl's birthday now.

[andrewprock]

I believe assuming they are "just going alphabetically" and/or that there is some sort of implicit moderator managing the conversation qualify as non-obvious assumptions.

[Nursie]

Assume nothing, simply take what's stated. This happened and then this and then this.

If you can't piece everything together then... well you're not suited to logical analysis.

[anigbrowl]

The vociferous objections on this sub-thread are rather amusing. It seems several people missed the bit where I said I was OK with the official solution at first, but kept being bothered about the problem construction. I doubt Andrew has any problem articulating the default 'correct' solution either. I was thinking about the problem construction anyway because I was annoyed that the problem as stated in Singapore includes several glaring errors of English grammar which were an annoying distraction, eg' I know that Bernhard does not know too' rather than '...does not know either.' English is an official language in Singapore so I was surprised that such obvious errors would be allowed to creep into a logic problem; it's akin to muddying up a mathematical equation with '-(-x)'.

That started me thinking outside the confines of the problem and about the implicit assumptions that were in the problem statement itself. The 'inability to piece everything together' is entirely imaginary on your part.

[andrewprock]

On the contrary, logical analysis is generally not well suited to the understanding of human behavior.

[Nursie]

If you think this is a question about human behaviour then you've gone very wrong indeed.

[andrewprock]

Given that this question is about humans, and discusses their behavior, it's clear you are making some assumptions about the structure of the question which are not present in the question.

That's certainly a reasonable thing to do.

What's not reasonable is to assume that the assumptions you make are going to match the assumptions of others. Likewise, when make assumptions there is a chance that the assumptions you make are incorrect.

That may or may not be the case here.

But the fact remains, you need to make some very strong assumptions for what you have said to be true.

[Nursie]

Nope, I'm not making assumptions, I'm using the data presented.

>> Given that this question is about humans

Please note that nowhere in the questions does it say the participants are human. This is one of your many assumptions.