TheVirtual-Physical Dichotomy 25 interface’ the virtual and the physical aspects of an interactive device, since the user sees the product itself as a unified physical/virtual system. But the rest of the physical world, and most of the bodily skills and experiencesof the user, lie outside this unified and definedworld.Usersare furtherlimited by a variety of factors, such as physical display constraints, input-output constraints, and social constraints. For example, physical display constraints mean that the user usually concentrates on only foregroundtasks with full access to only a single display surface. The evolution of interaction techniques has largely also been the history of improving the usability and appeal of the WIMP-based GUI. These work well in manysituations, mostobviouslyandimportantlyformanykindsofofficeorsimilar work. The work and the style of interaction have co-evolved and reinforced each other: we do the work we do becauseof the tools we have,and we have the tools we havebecauseoftheworkwedo. Several researchers have discussed ways to modify or even escape from this self-perpetuatingtrendandhave,forexample,experimentedwithsensor-basedtech- niques for interacting with virtual entities via the manipulation of physical objects in space (e.g. Ishii 2008; Ishii et al. 1998). Most of the broad range of new interfaces developed by HCI researchers are presented as alternatives to the current GUI paradigmandtry,inonewayoranother,todivergefromtheWIMP-basedapproach (Jacob et al. 2007). Better approaches for many types of people, including those with special needs such as the elderly and the socially or physically handicapped, draw on other principles such as free body movement, de-centralised displays, and tacit knowledge (Zacks et al. 2007; Schacter 1987; Benjamin et al. 1994). We can find numerous emerging post-GUI/WIMP interaction styles, and they constitute a huge growing trend in the HCI literature, because of their clear advan- tages of bringing more real, more tangible and more usable interaction. Typical examples are; augmented reality, tangible interaction, ubiquitous and pervasive computing, context-aware computing, handheld, or mobile interaction and so on (Jacob et al. 2008). Recently, we have witnessed the emergence of a wider variety of HCItechnologies,includinghandheldsmartphoneswithmoreintuitiveonscreen interfaces, which are pervasively penetrating into our everyday life. Technology creates the virtual world, but also exists in the physical world with which the virtual often competes for our attention. Many of these new interaction styles clearly exhibita combinationofthephysicalandthevirtual,sometimescalled mixed reality. Today mixed realities of various kinds are an increasingly prevalent approach to interaction that strives to combine the physical and the virtual. Mixed reality is also a growing object of study for the HCI research community, as part of a widespread effort to develop viable and more flexible alternatives to WIMP-based GUIs. But do these interaction styles really have many benefits for those who use them?Intermsoftheperceptualandpsychologicalaspectsofuse,theeffectofthese post-WIMPinteractionstyles has yet to be fully studied and understood. Another post-WIMP trend is that digital media are becoming more pervasive in ourbuilt environments,and include devices such as video screens, electronic access systems, andsensor-basedsmartenvironments.Butthereisstill ahugegapbetween the digital media and humans as bodies in physical space.