People continuously experience the world and the objects in it through all their senses. Product designers can influence the way people experience products by paying attention to the multiple sensory aspects of product design. Designing sensory experiences can be aimed at communicating a consistent message to all sensory channels, making this message a stronger one. The opposite approach, designing a product in a way that incongruent information is provided to different senses, can be used as a means to create surprising products. Perceiving one sensory aspect of a product first can create an expectation on what will be perceived through other sense modalities. The information perceived at a later stage may disconfirm the expectation formed upon the initial perception, resulting in a surprise reaction. In this thesis, three types of sensory incongruities were studied: visual-tactual, visual-auditory and visual-olfactory. Our studies suggest that out of the three types of incongruities that were studied, visual-tactual incongruities in products are most effective in evoking surprise reactions. Furthermore, the surprise reaction seems to have a long-term effect on 3 other emotions: interest, fascination and confusion. From the experiments on visual-auditory and visual-olfactory incongruity we concluded that people seem less likely to experience surprise upon encountering one of these types of sensory incongruities. Nevertheless, the sound of a product can in some cases influence the overall perceived expression of that product. Designers should always carefully consider whether to design a sensory incongruity or a product that communicates a consistent message to all sensory channels.