Pourang Irani

Improvements in motor performance achieved through motor imagery, the mental rehearsal of movement, are typically smaller than an equivalent dose of physical practice. One reason for this difference may be lack of feedback during motor imagery, integral to refining the motor plan, including knowledge of results. Here, we tested whether visual feedback provided via virtual reality impacted learning of a complex novel skill using motor imagery. Healthy novice participants (N = 48) were randomly assigned to one of three groups and engaged in four sessions of motor imagery practice of a golf putting task in a virtual environment. Following each motor imagery trial, participants observed one of three types of visual feedback: perfect feedback (100% success), erroneous feedback (30% errors, 70% success), or no feedback (control). Performance, measured by percentage of holed putts (%Success), mean radial error, and bivariate variable error, was assessed during three physical test blocks: before (pre), after (post), and minimum 24h after imagery practice (retention). Linear mixed effects models and accompanying Cohen’s d effect sizes conducted to quantify changes in performance revealed improvements in %Success by all groups at both the post-test (particularly the erroneous feedback group) and retention test with no effects related to mean radial error or bivariate variable error. Findings suggest that supplementing motor imagery with visual feedback may lead to greater task success. Future research should explore impacts on movement quality (e.g., arm, trunk kinematics) and trajectory-based learning. Overall, this work has implications related to the use of virtual reality to enhance the effectiveness of motor imagery.

Shape-changing displays typically lose pixel density as surface area expands, limiting their usability. We introduce MorphSkein, a shape-changing after-image display that preserves initial density (1.44 px/cm ² ) across naturally occurring axisymmetric shapes generated by spinning cables (troposkeins). The system uses a telescopic pole and four LED-strip rewinders on a rotating base. As the strips spin, centrifugal force forms troposkeins, and persistence of vision creates 360°-visible displays, while adjusting pole height and strip lengths changes their shape. As surface area grows, pixel density is preserved vertically by releasing new rows from the rewinders and horizontally by rendering extra columns per revolution with the strips. This keeps comparable density along the central horizontal line of the display, with naturally higher density toward the top and bottom where the troposkein curves inward. Because the technique relies on a mathematical model assuming ideal troposkein geometry, angular velocity becomes critical: incorrect speeds degrade pixel density accuracy, axisymmetric shape fidelity, or both. Interpolation of experimental data shows that 69.44% of reachable troposkein configurations achieve ⩾90% density accuracy and shape fidelity for at least one operating speed. Remaining cases degrade due to insufficient motor speed or limited MCU speed and LED refresh rate. Limitations and improvements are discussed.

Conventional Mixed Reality (MR) workspaces are frequently organized in cockpit-like layouts, where multiple floating windows surround the user. While this configuration facilitates access to digital content, it often induces occlusion, reducing understanding of the physical environment and limiting access to real-world objects. To overcome this challenge, we present the Contour-Adaptive Mixed Environment Overlays (CAMEO), a contour-adaptive MR interface that drapes virtual windows onto physical surfaces. This design integrates digital content with nearby items, thereby improving users’ visual access to background objects and supporting interaction with them. We evaluate CAMEO in two controlled studies. The first demonstrates that draping reduces hand-movement detours relative to flat mid-air surfaces, enabling more direct interaction with nearby items. The second shows that controlled window deformation does not significantly impair text legibility when compared to flat surfaces. Together, these findings contribute a novel design paradigm for MR workspaces that balances immersion, readability, and environmental understanding.

Micro Data Videos (mDVs) are up to one-minute data-driven vertical video clips for mobile devices. Widely adopted on social media platforms, mDVs hold significant potential for disseminating information. Despite their growing prevalence, little is known about their components and how they are designed. Thus, two studies were conducted. Study 1 analyzed 40 mDVs and revealed their narrative components. Study 2 examined, through design sessions with design experts, how such components are assembled to craft storyboards for mDVs. The diverse narrative styles of mDVs render them flexible and suitable for multiple topics and purposes. Further, many include a “Linker" directing viewers to external online resources. Participants approached their design in a structural yet iterative manner with emphasis on setting up a “hook” in the opening seconds to capture attention. We summarize and share common design practices used in creating mDVs, an increasingly important medium in data storytelling.

Designing a comfortable, familiar, and efficient one-handed text entry method for Head-Mounted Displays (HMDs) remains a significant challenge. Existing midair typing systems induce fatigue, while novel techniques often demand extensive training or sacrifice input efficiency. Consequently, we introduce ThumbSwype , a novel thumb-to-finger text entry technique that adapts smartphone swipe typing for HMDs. Users see the traditional QWERTY keyboard overlaid on their index, middle, and ring fingers, allowing them to perform swipe gestures with their thumb to type words. In an evaluation study (N=16) , participants achieved a mean of 14.52 words per minute (WPM), which is 63.8% of their smartphone swipe-typing performance, with a peak average of 20.2 WPM. We compare ThumbSwype’s performance with related work, and discuss directions for future improvement.