Using a 'task irrelevant probe' -- a 50 millisecond-long flash of light -- Vogel and a colleague were able to determine where exactly a subject's attention was focussed.

All of the subjects were able to quickly and accurately identify the targets when the objects moved around the screen, but as distracting components were added some maintained accuracy while others diverted their attention and slipped in performing the assigned tasks.

These findings were published in the Journal of Neuroscience.