Science Daily reports (here) on a paper in Nature Neuroscience, A central role for the lateral prefrontal cortex in goal-directed and stimulus-driven attention, by C. Asplund and group. They investigated being made temporarily blind by surprises.

“The simple example of having your reading interrupted by a fire alarm illustrates a fundamental aspect of attention: what ultimately reaches our awareness and guides our behavior depends on the interaction between goal-directed and stimulus-driven attention. For coherent behavior to emerge, you need these two forms of attention to be coordinated… We found a brain area, the inferior frontal junction, that may play a primary role in coordinating these two forms of attention.”

… the research team asked individuals to detect the letter “X” in a stream of letters appearing on a screen while their brain activity was being monitored using functional magnetic resonance imaging, or fMRI. Occasionally, an image of a face would unexpectedly interrupt the stream. The surprise caused the subject to completely miss the “X” the first couple of times, despite the fact they were staring directly at the part of the screen on which it appeared. They were eventually able to identify it as successfully as when there was no surprise. …the inferior frontal junction, a region of the lateral prefrontal cortex, was involved in both the original task and in the reaction to the surprise.

“What we think might be happening is that this brain area is coordinating different attention systems — it has a response both when you are controlling your attention and when you feel as though your attention is jerked away.”

“What we show is the dark side or negative impact of the orienting response. We found it blinds you to other events that can occur soon after the presentation of the surprise stimulus.,” The researchers hypothesize that we may be temporarily blinded by surprise because the surprise stimulus and subsequent response occupies so much of our processing ability. “The idea is that we can’t attend to everything at once. It seems that the inferior frontal junction is involved in this limitation in attention.”

The new research supports previous work by Marois’ laboratory that found the interior frontal junction plays the role of an attentional bottleneck — limiting our ability to multitask and attend to many things at once.