[doug*platypus]

We know little about Deagol, except that he was (in his own mind) generous with his birthday present to his friend, and not a match in strength for a humble river-fish. There could hardly be a plausible need for Deagol to give the Ring up to Smeagol simply because he asked for It. It need only have been pretty and desirable, and not magical for Deagol to desire to keep It for himself. Of course, it's possible that he was so captivated by the Ring that he was oblivious to the danger he placed himself in by withholding It from Smeagol. As for the Ring "calling" to Smeagol, I think that's personifying It just a little too much. From what we are told in the books, the Ring itself is constantly trying to return to Sauron, not to gain a new master. It would be hasty for It to presume that Sauron had a better chance of recovering It from Smeagol's hands; if It did indeed think that, It was wrong in the end anyway.

Rather than the Ring "calling" for Smeagol, I think that he was drawn to It by feelings that were in himself, and in many others. Greed and envy. The Ring was attractive to many people.

An interesting point has been raised that the Ringbearers each started off their ownership of the Ring under different circumstances. Might make/have made a good topic.