Virtual vs. Physical Touch Experience

A person touching a screen and a person holding a piece of wood

Most of the emerging paradigms in input-output since the invention of the mouse try to enable more direct relationships between the human body and digital objects. This direct interaction is essential because it defines our experiences with the world. People’s earlier steps of understanding the world is thought direct touch of physical objects. These interactions nowadays have become more concentrated on the digital environment as more often our work is done in the digital space. Touch and Tangible User Interface (TUI) communities frequently discuss several relevant phenomena, including embodiment, intuitiveness, and naturalness. These phenomena, though sometimes controversial, are often considered fundamental to the design and experience of using touch and tangible interaction in the digital world. However, there is little empirical evidence confirming these high-level ideas, and how they could affect our perception of the digital environment. The decisions and actions that we take while interacting with the digital world are currently underexplored, and it is difficult for designers to draw conclusions about how these ideas could help to better design the tactile user experience. In our project, we aim to explore and understand psychological and perceptual phenomena using existing psychological effects that could be replicated in the digital environment, then observe how these effects change when using tactile interaction techniques.

A common mantra for these new technologies is that they allow us to become more embodied with the digital world and better leverage the natural motor and body skills of humans for digital information manipulation. While we have begun to have a firm grasp on the philosophical implications of these advances, we don’t yet have a good understanding of the psychological phenomena and mechanisms at work. Moreover, there is very little quantitative evidence from human-computer interaction that these more “direct” modes of interaction actually result in interaction that is more similar to real-world physical object manipulations. As a result, we are still missing important evidence that would allow us to answer questions such as the following:

  • How do virtual artifacts affect human psychology when manipulated through direct touch?
  • Is there a quantitative difference between interaction with technology through a physical object (tangible computing) and through screen touch?
  • Is there any psychophysical advantage to the separation of the digital and the physical, or an advantage to input “indirectness”?

In this project, we attempt to break ground in finding quantitative evidence regarding the relationship between interaction with physical objects and interaction with virtual objects in a psychophysical sense. This evidence can be useful for the design and evaluation of input systems. As a first step, we take the phenomenon of figural after effects—changes in human perception resulting from grasping or holding physical artefacts, well studied in psychology—and use a controlled laboratory experiment to observe whether the effect applies to virtual object representations accessed through multi-touch screens.

Our results show that the psychophysical effects of virtual touch are not comparable to those of holding a physical object. The findings indicate a measurable qualitative difference between virtual and physical artifacts that has important consequences for the design of interactive systems. We highlight several consequences of this finding, including both psychophysical advantages of tangible interfaces over virtual ones, as well as potential benefits of virtual interfaces due to reduced perceptual interference.