Visual information overload is a threat to the interpretation of displays presenting large data sets or complex application environments. To combat this problem, researchers have begun to explore how haptic feedback can be used as another means for information transmission. In this paper, we show that people can perceive and accurately process haptically rendered ordinal data while under cognitive workload. We evaluate three haptic models for rendering ordinal data with participants who were performing a taxing visual tracking task. The evaluation demonstrates that information rendered by these models is perceptually available even when users are visually busy. This preliminary research has promising implications for haptic augmentation of visual displays for information visualization. Categories and Subject Descriptors H.5.2 [User Interfaces]: Haptic I/O General Terms Human Factors. Keywords Haptics, 1-DOF, tangible user interface, graspable user interface, haptic perception, multimo...