In the long history of subliminal messages and perception, many contradictory results have been presented. One group of researchers suggests that subliminal interaction techniques improve human–computer interaction by reducing sensory workload, whereas others have found that subliminal perception does not work. In this paper, we want to challenge this prejudice by first defining a terminology and introducing a theoretical taxonomy of mental processing states, then reviewing and discussing the potential of subliminal approaches for different sensory channels, and finally recapitulating the findings from our studies on subliminally triggered behavior change. Our objective is to mitigate driving problems caused by excessive information. Therefore, this work focuses on subliminal techniques applied to driver–vehicle interaction to induce a nonconscious change in driver behavior. Based on a survey of related work which identified the potential of subliminal cues in driving, we conducted two user studies assessing their applicability in real-world situations. The first study evaluated whether subtle (subliminal) vibrations could promote economical driving, and the second exposed drivers to very briefly flashed visual stimuli to assess their potential to improve steering behavior. Our results suggest that subliminal approaches are indeed feasible to provide drivers with added driving support without dissipating attention resources. Despite the lack of general evidence for uniform effectiveness of such interfaces in all driving circumstances, we firmly believe that such interfaces are valuable since they may eventually prevent accidents, save lives, and even reduce fuel costs and CO2 emissions for some drivers. For all these reasons, we are confident that subliminally driven interfaces will find their way into cars of the (near) future.
How Long Does It Take to Relax? Observation of Driver Behavior During Real-World Conditionally Automated Driving
