Few experiments have been performed to investigate near-field egocentric distance estimation in an Immersive Virtual Environment (IVE) as compared to the Real World (RW). This article investigates near-field distance estimation in IVEs and RW conditions using physical reach and verbal report measures, by using an apparatus similar to that used by Bingham and Pagano [1998]. Analysis of our experiment shows distance compression in both the IVE and RW conditions in participants' perceptual judgments to targets. This is consistent with previous research in both action space in an IVE and reach space with Augmented Reality (AR). Analysis of verbal responses from participants revealed that participants underestimated significantly less in the virtual world as compared to the RW. We also found that verbal reports and reaches provided different results in both IVEs and RW environments.

The novel, salient haptic skills simulator improved the precision and accuracy of participants when applying forces with the simulator. These results suggest that the simulator may be a viable tool for laparoscopic force skill training. However, further work must be undertaken to establish full validity. Nevertheless, this work presents important results toward addressing simulator-based force-skills training specifically and surgical skills training in general.

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Distances are regularly underestimated in immersive virtual environments (IVEs) [Witmer and Kline 1998;Loomis and Knapp 2003]. Few experiments, however, have examined the ability of calibration to overcome distortions of depth perception in IVEs. This experiment is designed to examine the effect of calibration via haptic and visual feedback on distance estimates in an IVE. Participants provided verbal and physical reach responses to target distances presented during three sessions; a baseline measure without feedback, a calibration session with visual and haptic feedback, and finally a post-calibration session without feedback. Feedback was shown to calibrate distance estimates within an IVE. Discussion focused on the possibility that costly solutions and research endeavors seeking to remedy the compression of distances may become less necessary if users are simply given the opportunity to use manual activity to calibrate to the IVE.

In minimally invasive surgery (MIS), it is critical to have the ability to accurately interpret haptic information and apply appropriate force magnitudes onto soft tissue in order to minimize tissue trauma. The surgeon's administration of force onto tissue reveals useful perceptual information which guides further haptic interaction making the force perception in MIS a dynamic process. It has been hypothesized that the compliant nature of soft tissue during force application provides biomechanical information denoting tissue failure. Specifically, the relationship between applied force and material deformation rate specifies the distance remaining until the tissue will fail, which is termed distance-to-break (DTB). Two experiments explored sensitivity to DTB; one with an exploratory task and the other using a unidirectional task. Findings revealed that observers could reliably perceive DTB in simulated biological tissues in the exploratory task but they were unable to perform the unidirectional task. It was also found that the perception of DTB can be improved through feedback training. Implications for optimizing training in MIS simulators are discussed.