Of the published research and science, three of the more popular theories in the last fifty years are behaviorism, cognitivism, and constructivism. The infographic below reviews the pros and cons of each approach while making a case for connectivism as a response to the age of the internet and information.
I like the theories visible in one place. Explains a lot in the comparison. Perhaps a little of all four is needed depending on the people involved in the learning situation.