Social touch in virtual reality

The sense of touch is a fundamental aspect of our everyday interactions, especially those that involve social relationships. Nothing now can (and hopefully will not have to) substitute for the beneficial effects of real skin-to-skin touch. However, there are conditions where simulated touch might, at least temporarily, be a resource for compensating the lack of real touch (e.g. under situations of social isolation) or to contribute to our knowledge of tactile perception and its effects on people. It is therefore not surprising that the study of touch within virtual reality (VR) applications is attracting growing interest among researchers. The visual aspects of VR, in terms of graphic design and interactions, are certainly well know, and progress in this field is running very fast. However, less knowledge is present in the field of simulated touch, especially under conditions of social interactions. Nevertheless, the possibility to provide the sense of touch to human users is central for the future progress and even acceptance of VR tools and simulated environments. This work aims to present an overview regarding the haptic technology available for the investigation of social touch in VR. This review is composed of two parts. In the first section we provide a brief introduction to the tactile technologies available, highlighting for each device its strengths and limitations. The second part presents a few examples of experimental studies in which these devices were used inside immersive VR experiences, to investigate the contribution of touch to social interactions. The discussion addresses the future development of realistic haptic technologies, as well the experimental hypotheses still to be tested in social psychology and neuroscience.