I was playing Zynga's Draw Something when I saw an interesting icon:
A quick search of "tying fingers" produces results such as:
This is a carry-over from olden days when people tied pieces of cloth around any painful part of their body.
This cloth was tied in one area to keep the “spirit of life” in that area, and so cure it and keep the pain from spreading to other parts of the body. The string on the finger was designed to “keep” the thought there, to be remembered later when it was needed.
which looks immediately dubious. But there are also some "scientific" (or pseudo-scientific) claims like the accepted answer in the other QA website:
- Yahoo Answers
It's a little known fact that the nerves that define your sense of touch on your index fingers are the ones with the quickest connections routed directly to the hippocampus, the part of the brain responsible for memory. Tying a ribbon around the index finger means you constantly have a texture that's activating those nerves and thus keeping that part of the brain in alpha (high activity) mode. If you tie the ribbon (or wear a ring on your index finger, or any such apparatus) at the very moment you are trying to memorize something you mustn't forget later on, it associates that brain activity with said memory, keeping that pathway almost exclusively as a conduit for that memory.