interesting question !
i guess maybe you're right... because if you would have to choose between a bar of chocolate priced 1€uro and a bar of chocolate priced 10Cent.... i guess not many people would take the 10 cent bar of chocolate - and even then it would be seen as inferior ! To know that the 10 cent bar of chocolate is as good as a 1€uro bar of chocolate requires that you've already tasted both !
And commonly we only buy a 1 €uro bar of chocolate... Thus we would assume that there's something wrong with the 10 Cent bar of chocolate ...

Same thing with games on steam... if for example half life 2 is on there for 10 Cent, everybody would buy it instantly ! But if some unknown shooter would be there for 10 Cent not many people would buy it, because something has to be wrong with it...

I guess without knowledge we(at least i) are cautious and thus we can miss a good deal....

of course if you have knowledge about games and you buy a game for 19.99€ that's objectively (and also from the point of view of the developer) only worth 4.99€, then I'd be pretty pissed off (of course only because I know that the game isn't worth that much)...

Thus I guess, if you want to sell the game to people who have some knowledge about games, keep the price low
If you want to sell the game to people who only occasionally play games, raise the price

this interesting video is roughly about this topic :
http://www.youtube.com/watch?v=FREh6GyHk1k