We like to think we have control over our thoughts in real time, instantaneously. The moment we think of doing something is the very same moment the neurons in our brains start firing, creating that intention. But this isn't how it works.
The time lag between your brain knowing what it's about to do and you being aware of it is shockingly long, often on the order of seconds. So every intention we have—going to the fridge to get a beer for instance—the intention to do so formed seconds before you were conscious of thinking about getting a beer. We are constantly living in the past moments of our brain.
Beyond the existential deep thoughts that might inspire, a group of German researchers are taking advantage of this quirk of nature and applying it to safer driving. They are experimenting with a system that taps into brain signals of drivers, monitors signs of an intention to brake, and then bypasses our slower conscious thought and even slower muscles to press the pedal. Their paper is published today in the Journal of Neural Engineering.
The scientists are using electroencephalography (or EEG)—a cap of electrodes attached to the head—to monitor brain waves. They found that the system can detect an intention to brake 130 milliseconds faster than it would take for that person to push the brake pedal. For highway driving at 60 mph this time gap translates into a distance difference of 12 feet, about the length of a compact car.
EEG has been used to monitor fatigue and mental workload in truck drivers and soldiers in the field, but it has never been tested with emergency signaling.
Scientists tested this system with 18 participants in a simulator. With EEG caps on their heads, subjects "drove" a car much like they might in a video game. Scientists also recorded the subjects' muscle activity with electromyography activity (or EMG.) Signals are triggered by muscle contraction and EMG can be used to detect intention to move before a leg actually moves.
Subjects were instructed to stay within 65 feet of a car in front of them, driving 60 mph on a windy, well-trafficked road. Randomly, the car in front would slam on its brakes, setting into motion a crisis situation. Scientists logged data from both the EEG and EMG and recorded the time it took to move from gas pedal to brake pedal and to decelerate the car. The researchers determined what parts of the brain are most highly sensitive to initiating braking. The initial reaction comes from the occipito-temporal area which involves visual perception, most from seeing the red braking lights of the car in front. Scientists noted a broad reaction within the parietal and occipital brain areas which translates to what they call an "oddball scenario" or something unexpected happening. Again, here the trigger is the sudden braking of the car in front. Activity in the motor cortex is then noted which indicates a plan to move one's leg, presumably in this case from the gas pedal to the brake. From this experiment the scientists conclude that it's absolutely possible to detect a driver's intention to brake, and of course this precedes any observable actions. By tapping into that intention signal an emergency braking system could be triggered that is significantly faster than our own.
Check out this video of one participant in the simulator. At around 46 seconds you'll see the spike in brain activity in response to seeing the red brake lights flash.
We have to remember of course, this is the lab. Real-world driving is much more dynamic and may provide extreme challenges to detecting signal. How accurately the EEG can detect the difference between normal and exceptional traffic situations has yet to be seen. Already there are many variables that might swamp out the neural signal from a braking light. For instance a sharp turn in the car, or the head and body movements of the driver can obscure the fine neural signal of intention. Also, the electrical activity caused by something as simple as chewing gum, raising an eyebrow, or winking can all wreck havoc with the ability for an EEG system to read neural signals associated with sudden braking.
Another issue is of course the EEG caps themselves. They are uncomfortable, like bathing caps, and they contain gooey gel so the electrical signals flow better. Plus they are just plain unattractive. The scientists assure us that this is improving. Currently there are companies working on dry caps that are much smaller and more comfortable. The researchers are already planning a real-world driving study, so we'll soon know whether our brains can drive better than we can.