Recently a colleague challenged the notion of locus of attention. He insists that the singularity of our attention is bounded by each of our sense, but not the overall consciousness. In the other words, a user can comfortably pay attention to information in the audio and visual channels at the same time.
Update (07/30/2007): I browsed through the chapter about locus of attention in ‘The Humane Interface’ and just as I thought, it contradicts my colleague’s claim. To make sure that information in the book has not passed it times, I posted the question to an online forum. Two designers and one lecturer in cognitive psychology also disagrees with my colleague’s claim. Human can perform trained task with another task and split the attention between them. That mechanism allows people to drive and carry a conversation at the same time. Splitting attention is an entirely different thing as having multiple attention.