Working on Multiple Teams at the Same Time: Positive or Negative?

Wharton Professor Martine Haas (a grad school classmate of mine) and Duke Professor Jonathan Cummings have published a new study about teams.  They collected original data within a multinational corporation about how people allocate their time among multiple teams on which they are serving.  According to Knowledge at Wharton, here is what they found:

The professors also discovered that highly skilled people were more likely to be involved in multiple teams, and that having members who were involved with multiple teams was associated with good team performance. A person with that kind of knowledge tends to be highly sought after, so his or her attention will likely be divided among many teams. And that's not necessarily a bad thing, says Haas. Teams composed of these valuable members also performed well. "That was a surprising result," she notes. "It's not necessarily causal, but it suggests if you take people who are assigned to several other teams already and bring them onto a new team, that team can benefit from their networks, knowledge and access to resources, even if they can't devote a lot of attention to the team. The exception is if the team members who are involved in lots of other projects are also very geographically dispersed -- in this case, the fact that they cannot devote much attention to the team makes the performance advantage disappear."

I find these results compelling, and they make sense intuitively.  I do wonder about one thing though.  Does it matter what TYPE OF WORK the teams are doing, or THE TIME CONSTRAINTS under which they may be operating?  Perhaps some types of work require more focused attention, while others benefit from people being able to access a wider network through service on multiple teams.  Similarly, perhaps working under a tight deadline could make it less attractive to serve on many teams simultaneously.