Electrotactile Improves Thermal Referral

TL;DR

This paper introduces electrotactile technology to enhance thermal referral in VR, overcoming vibrotactile limitations by improving cold sensation referral, realism, and tactile perception in immersive environments.

Contribution

It presents a novel electrotactile approach for thermal referral, demonstrating its advantages over vibrotactile methods through user studies and providing design guidelines for VR applications.

Findings

Electrotactile increases cold sensation referral rate.

It enhances thermal perception while reducing tactile buzz.

Improves realism for contact and non-contact thermal events in VR.

Abstract

Thermal referral enables thermal sensations in locations lacking thermal actuators--this is achieved using vibrotactile actuators to redirect a nearby thermal sensation to where a tactile sensation is applied. However, we found that its reliance on vibration introduces critical limitations: it struggles to produce cold referral, and the inherent strong tactile "buzz" makes it unsuitable for simulating non-contact thermal events, such as the chill of an open freezer in VR (in contrast to contact-based thermal events like touching the freezer's cold handle). To improve this, we propose a shift from vibrotactile to electrotactile-based thermal referral. We evaluated in two user studies--a psychophysics experiment (N=22) and a VR deployment (N=20)--where we contrasted electrotactile with vibrotactile-based thermal referral. Our results reveal key advantages of the electrotactile based thermal referral: (1) increases the referral rate for cold sensations; (2) increases thermal perception while minimizing tactile; and (3) improves realism across a range of VR thermal scenarios, specifically distinguishing between contact-based and non-contact thermal events. Finally, we provide design guidelines for choosing tactile cues to create immersive multimodal thermal experiences in VR.