Multimodal interfaces have long held the promise of enhanced and effective human machine interaction. The ultimate goal of multimodal interfaces is to facilitate human activity allowing seamless exchange of information. This goal requires a coordinated development effort that incorporates a thorough understanding of human perceptual system in the design of interfaces. In this manner, multimodal interfaces can supplement and expand current paradigms in human computer interaction. A novel framework is, therefore, proposed for design, development and evaluation of perceptual interactions between human and the computer. The proposed framework hopes to enable interfaces that aim to `fit' and `adapt' with the human perceptual system. An empirically driven conceptual approach is used to derive guidelines, create artefacts, and develop models for these perceptually adaptive interfaces. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation]: User