The other way, well as ye point out, humans work by knitting logic to emotion. ......... In this context, a 3-5% difference in a board's performance is a bigger difference than it first sounds.
Now we're getting somewhere. Ross Gittins has a great article in the SMH today about this very matter. Bugger getting a link for you, look it up yourself. The essence of the article is that emotion wins the argument just about every time, although sometimes it lets rational mind think it got its way, and very occasionally it lets rational man win a small victory.
So I decided I wanted to be a short boarder. Why - emotional decision. After a few boards I had worked out what length of board suited me best and how much volume required, but after that the whole science of hydrodynamics is so complex. So I bought the board that fulfilled the volume and length criteria "that looked like my board". The one that spoke to me in a primal way, that evoked a visceral reaction. The one that looked the fastest (or coolest? status anxiety - even if I can't surf I have a cool looking surfboard)
The only thing unique about it was that I was consciously, rationally, making an emotional decision. It was aesthetic. I let myself fall into the emotion of it all. Besides, who is to say that there isn't any ancient wisdom within your cells that tells you what will glide over water efficiently and what wouldn't. Every gene in every cell is descended from some aquatic creature, assuming evolution is all that science says it is.
Nick comments that a 3% to 5% difference might be quite noticeable. I find that surprising. I think the psychological impact about how you 'feel' about the board is so much greater than the actual performance of the board (and how could performance honestly be measured as it is the knitting of a human,a particular time, a particular mood, a particualr wave and a stick of foam)
What you say is rational Nick, that's probably the greatest weakness in your observation.
Here's a crazy thought. What if the next great leap in design and materials lead to the development of 'the brick'. The newest sensation, it outperforms every water craft ever known to man by 1000%. Hydrodynamic tests prove it works, it's just that it looks like a brick, shaped approximately like a large brick that you paddle. The secret is that it is a new material, and for some unknown reason, only the brick shape works with this new material, but how good is it, and it's cheap too.
Do you think that everyone will be down the beach with their new 'brick' surfboard, or will you stay with something that looks right, even if it doesn't perform as well.
I think I would stay with my current boards, but I'm an emotional guy.