Chuckle, the attention span of these 13-14 year olds is measured in minutes. Assuming they aren't even younger and falsifying their age, which is not unlikely...
And as Don says below, the super young are here mainly not for advice, but to get validation.. so they have no reason to wait once someone agrees with them.
There's no way to assess how many people who are older leave the site because they're here for an advice site, not a Facebook tag your friends scene. \ Sure the overall membership is higher since they got rid of any age requirement, but how long does the average 13-14 year old stay on Gag? I'm guessing weeks... there's always a more trendy site for people in that age group.
We actually get a prompt from gag if we don't appoint a MHO within the day! I found that annoying since it took about a week for me to get a legit answer that didn't involve any in appropriate language!
I wouldn't say it necessarily has to do with age but the people themselves. I've seen all sorts of age groups give MHO fast. I've also seen users who don't give MHO at all.
I have no idea why people would give a super fast MHO in the first place though, considering that is basically just creating less answers for yourself. I don't think it has to do with attention span for the most part, but who knows. I always thought of it being more that they don't want the notifications (assuming they aren't doing it for a reason like them being embarrassed of the question and want to get rid of it).
I tend to answer questions in the topic feeds and work back through them so I am only looking at recent questions about 10% of the time. There has been the odd occasion I thought "Wow that was fast for a MHO" but have to be honest I didn't notice any common factor like the asker's age - I have always felt the whole MHO process was flawed but it is one of those ones, I am not too sure of a way around it maybe a 24 hour delay on being allowed to award MHO but then they mightn't bother. I honestly feel that the true MHO awards are very low numerically sometimes when I get a MHO it seems like I was just in right place at right time rather than the quality of my answer,