The concurrent think-aloud protocol—in which participants verbalize their thoughts when performing tasks—is a widely employed approach in usability testing. Despite its value, analyzing think-aloud sessions can be onerous because it often entails assessing all of a user's verbalizations. This has motivated previous research on developing categories to segment verbalizations into manageable units of analysis. However, the way in which a category might relate to usability problems is currently unclear. In this research, we sought to address this gap in our understanding. We also studied how speech features might relate to usability problems. Through two studies, this research demonstrates that certain patterns of verbalizations are more telling of usability problems than others and that these patterns are robust to different types of test products (i.e., physical devices and digital systems), access to different types of information (i.e., video and audio modality), and the presence or absence of a visualization of verbalizations. The implication is that the verbalization and speech patterns can potentially reduce the time and effort required for analysis by enabling evaluators to focus more on the important aspects of a user's verbalizations. The patterns could also potentially be used to inform the design of systems to automatically detect when in the recorded think-aloud sessions users experience problems.

We present a new handheld haptic device, Thor's Hammer, which uses propeller propulsion to generate ungrounded, 3-DOF force feedback. Thor's Hammer has six motors and propellers that generates strong thrusts of air without the need for physical grounding or heavy air compressors. With its location and orientation tracked by an optimal tracking system, the system can exert forces in arbitrary directions regardless of the device's orientation. Our technical evaluation shows that Thor's Hammer can apply up to 4 N of force in arbitrary directions with less than 0.11 N and 3.9° of average magnitude and orientation errors. We also present virtual reality applications that can benefit from the force feedback provided by Thor's Hammer. Using these applications, we conducted a preliminary user study and participants felt the experience more realistic and immersive with the force feedback.

It is well-known that tasks imposing high cognitive load, i.e., the mental effort required to carry out a task, place a strain on people's ability to perform. In light of this, the present study investigates whether poor performance also occurs in human-computation games. That is, do players perform better in game designs that increase the visual information presented? These designs have the advantage of exposing players to more of the solution space, but may come with the caveat of imposing a higher cognitive load. We present a case study by considering alternative layouts differing in the amount of visual information given to players in a human-computation game. The findings of the study seem to support the idea that presenting more information is beneficial to players. This is surprising result that challenges prevailing beliefs about cognitive load, and invites more detailed, future investigation.