How do humans learn to combine tasks? I've been reading about hierarchical learning (a variant of reinforcement learning from what I understand) and how it is shown to allow learning of a higher-level task (the main example is assembly). I made the mistake of assuming that since the paper shows how a set of sequential actions are learned more quickly when the individual tasks are learned beforehand, that the same could be accomplished with a set of tasks to be combined.

For example, imagine learning to play hockey. First, you have to learn how to skate effectively. Secondly, you learn how to handle the puck with a stick. Thirdly, you have to learn to be aware of the other players and their movement. Finally, you combine all of these and sometimes have to spend time refining the lower end skills to become an effective hockey player.

Is there a name for this type of learning and a model associated to it? Is this type of learning encompassed in hierarchical learning?
The term I was looking for is "concurrent activities". Some research in the domain of hierarchical learning has been done in this domain by Rohanimanesh and Mahadevan.

According to this literature review on hierarchical learning, basically what they did was determine how multiple tasks can be managed without interfering with one another and how they should be scheduled.

I couldn't find any cognitive models of this concurrency, so there appears to be quite a bit of work done on the idea of multi-tasking, which might be synonymous. Unfortunately, most of this seems to be quite firmly in the camp of the Classical Cognitive Science Paradigm (such as the work by Niels Taatgen which interestingly rejects hierarchy) with not a lot of thought put into neurobiological plausibility. Additional answers pointing to fMRI experimental data similar to the one found here for hierarchical learning would be greatly appreciated.