Trade-offs in the design of multimodal interaction for older adults

This paper presents key aspects that designers and Human–Computer Interaction practitioners might encounter when designing multimodal interaction for older adults, focusing on the trade-offs that might occur as part of the design process. The paper gathers literature on multimodal interaction and assistive technology, and describes a set of design challenges specific for older users. Building on these main design challenges, four trade-offs in the design of multimodal technology for this target group are presented and discussed. To highlight the relevance of the trade-offs in the design process of multimodal technology for older adults, two of the four reported trade-offs are illustrated with two user studies that investigate mid-air and speech-based interaction with a tablet device. The first study explores the design trade-offs related to redundant multimodal commands in older, middle-aged and younger adults, whereas the second one investigates the design choices related to the definition of a set of mid-air one-hand gestures and voice input commands for older adults. Further reflections highlight the design trade-offs that such considerations bring in the process, providing an overview of the design choices involved and of their potential consequences.