Student distribution

Geneticist Johnjoe McFadden writes in the Guardian on some experimental economics research which suggests that thinking about money makes people more self-sufficient but also more selfish and less sociable.

McFadden notes:
Most student allocators proposed a fairly even split, keeping an average $5.44; but students majoring in economics tended to be greedier, proposing to keep an average $6.15. Conversely, when they were on the other side of the table, the economists tended to accept less, as little as $1.70 (compared to $2.44), before throwing their arms up in outrage. It seems that studying money makes you less generous, or perhaps the discipline attracts less generous people who give less and expect less in return.

The worrying thing here is that economics students make up the largest part of subjects for economic experiments - they're the closest and most available pool for university researchers, and they're most likely to be willing to take part (especially if there's some money involved), as I did last year. But if economic students are distinct from the general population, then would this not introduce a significant bias into the whole field of experimental economics?