I have been drafted in to provide UX feedback on a recently completed website. One point I made was that red was not a suitable colour for a positive action, i.e. completing a form. The reply cited this article
The reason why 2.0 kept pushing the red button – besides the fact that he likes to torture anyone over 3 feet – is that it was red and the other buttons are black. Red is a very good color for checkout and form buttons. In the reptilian brain, red signifies blood. Blood is good. It means you killed something and will get to eat dinner tonight along with your cave woman.
What is everyone's thought on this? My initial reaction is that it could cause confusion. Is red really a good colour for a positive action? Will it really increase conversions?