[Big Poppa Smurf]

ed,

it's probably both. everyone knows what pre-meds are like and that it's hard work, so it filters out people whose personality is not like that. Then since it's a lot of work some people probably get ruined.

Also, the people who have the "pre-med" personality are also those most likely to make sure you know they're a premed. The cool premeds probably don't talk about it as much or so obnoxiously.