Visual motion adaptation can impair decision making in driving

Drivers are often faced with decisions, which have potentially life-threatening consequences. Accident reports indicate that errors in decision-making during driving (e.g., deciding whether or not to pull out in front of another vehicle) are the probable cause of the majority of accidents on our roadways. One possible source of these errors of judgment is that in some situations the information provided by the human visual system is inaccurate. We have previously shown that staring straight ahead during simulated driving on a straight open road can give the driver the illusion that the time to collision with other vehicles is longer than it really is. This effect occurs because the neural mechanisms in the human visual system sensitive to time to collision with an approaching vehicle become adapted to closing speed. Here we show that this closing speed after effect can impair the ability of a driver to decide whether there is sufficient time to (i) overtake another vehicle on the highway and (ii) execute a left-turn in front of oncoming traffic. Closing speed adaptation resulted in decisions that were delayed, of higher risk, and more variable.