To whatever extent that people in the 1920s can be said to have had algorithms for machine learning, they certainly didn't bear any relation to modern algorithms.
Even the idea of requiring enough data to build a good system is fairly new. As late as the 1980s, expert systems were the dominant approach to artificial intelligence, and they didn't require information corpi at all but instead involved experts programming in all of the rules they could think of for a system.
Do we know who published the first conceptual framework for the algorithms behind AlphaGo etc? It seems like they would get a Nobel prize at some point…
Even the idea of requiring enough data to build a good system is fairly new. As late as the 1980s, expert systems were the dominant approach to artificial intelligence, and they didn't require information corpi at all but instead involved experts programming in all of the rules they could think of for a system.