To cope with the rising volume of information in humancomputer interfaces, explicit and attentive interaction is more and more frequently replaced by implicit means of information exchange, supported by context-and activity-aware systems and applications. The trend of excessive information is, however, still ongoing, calling for further solutions to reduce a persons cognitive load or level of attention. Subliminal interaction techniques are considered a promising approach to deliver information to a person without causing much supplementary workload. This workshop aims at discussing the potential of subliminal perception to improve the information flow for human-computer interaction in the light of the fact that, up to now, the results have been mixed. One group of researchers has provided evidence that subliminal stimulation works, but the other has found that it does not, or even cannot, work. To clarify this issue, experts from various domains attending the workshop will discuss how subliminal effects can be scientifically supported or how a certain claim could be empirically refuted.