Unconscious pop-out: Attentional capture by unseen feature singletons only when top-down attention is available, is the title of a paper about to be published. When the paper appears it will likely be unavailable to me, but if I can read it, I will post again with more detail. Here is most of the press release:

Paying attention to something and being aware of it seem like the same thing -they both involve somehow knowing the thing is there. However, a new study, which will be published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science, finds that these are actually separate; your brain can pay attention to something without you being aware that it’s there.

“We wanted to ask, can things attract your attention even when you don’t see them at all?” says Po-Jang Hsieh, co-author… Usually, when people pay attention to something, they also become aware of it; in fact, many psychologists assume these two concepts are inextricably linked. But more evidence has suggested that’s not the case.

To test this, Hsieh and his colleagues came up with an experiment that used the phenomenon called “visual pop-out.” They set each participant up with a display that showed a different video to each eye. One eye was shown colorful, shifting patterns; all awareness went to that eye, because that’s the way the brain works. The other eye was shown a pattern of shapes that didn’t move. Most were green, but one was red. Then subjects were tested to see what part of the screen their attention had gone to. The researchers found that people’s attention went to that red shape – even though they had no idea they’d seen it at all.

In another experiment, the researchers found that if people were distracted with a demanding task, the red shape didn’t attract attention unconsciously anymore. … “We need to be able to direct attention to objects of potential interest even before we have become aware of those objects,” he says.

What appears to be the gist of the paper is that bottom-up, perception driven, and top-down, task driven, attention can be ‘active’ at the same time; the bottom-up, in this case, determining what reaches awareness and the top-down being independent of awareness. It has been a question in my mind for some time – is attention an integral part of consciousness or just part of its preparation (like perception). This work seems to imply the later, that attention and consciousness are separate processes which interact.