Shape blind?

The other day, I had a friend over. He had a small digital camera made by the same company as mine. It was a different model but the memory cards were the same. I didn't have the software or connector for his, and he wanted to offload his full, memory card. So, I took out the card from my camera (which was white) and switched it with his (which was blue) in order to upload his card on to my computer. No problem, but when I gave him his card back (the blue one,) I looked on the table for my card and I couldn't see it, I started looking around to see where else it wasn't, when my friend said "It's here on the table." Then I realized that I was looking for something blue. My friend is colour blind and looks for shapes, not colour, and saw the square shape on the table instantly. I wonder if colour blindness gives one an advantage in shape recognition, because they aren't distracted by vivid colour.