Exploring the potential of new digital technologies for teaching and learning in order to develop new educational resources is an internationally present field of educational research and integral objective of the European agenda “Opening up education” (European Commission, 2020a): Research on the suitability of technical innovations for the use in scholar situations can provide valuable evidence about opportunities and challenges of the use of ICT in education (European Commission, 2020b). Augmented Reality (AR) is an emerging technology that allows for real-time integration of real and virtual objects in the field of view (Azuma, 2001). Although AR appears to be beneficial for promoting learning (Garzón & Acevedo, 2019), the practical use is still impaired by various technical problems: AR-devices and applications can be difficult to use (Munoz-Christobal et al., 2015), especially when poor technical gesture (or other input) recognition obstructs the handling of the devices (Chang et al., 2014). In the model of usefulness of web-based learning environments by Nielsen (1993), those crucial technical aspects of the use of AR-devices are summarized by the term usability. Depending on a technology’s usability, the learning may be either facilitated or hampered (Bourges-Waldegg et al., 2000). As not only the physical body characteristics (e. g., arm length or hand size), but also the state of cognitive development in terms of motoric skills or spatial cognition differ between young children and adults (Radu & MacIntyre, 2012), technical difficulties and peculiarities of AR-devices must be specially examined for young children. A major research desideratum is the evaluation of potential benefits and challenges of using head-mounted immersive AR-devices (HMD-AR) (Akçayır, M., & Akçayır, 2017).

The present study focuses on the Microsoft HoloLens2, which is a new model of HMD-AR-glasses. Announced improvements in terms of software for gesture and voice recognition indicate an increased potential to be suitable especially for the use with young children but an empirical evaluation is still missing. In contrast, research on the previous model HoloLens1 has shown that the technology requires further improvement, especially in terms of voice recognition, as the children’s voice is higher than an adult’s voice (Munsinger et al., 2019). The present research focuses on two major usability aspects of the HoloLens2 for the target group of primary school children:
First, we present results on differences in the technical performance of three possible interaction methods with AR-objects provided by the HoloLens2. In comparison to the previous model (HoloLens1), which allowed control via gestures, remote clicker and voice commands, the HoloLens2 offers direct interaction with the AR-objects, but also gesture and voice commands. The resulting leading research question is “How do the three interaction methods of the HoloLens2 differ in terms of their technical performance with children of primary school age?”
Secondly, we present results on special technical and physical peculiarities of the use of the HoloLens2 with young children that may occur due to the children’s physical conditions like a higher voice or smaller arms and hands. The second leading research question is therefore: “Which technical errors occur during the use of the HoloLens2 with children of primary school age?”
The research questions are examined by analyzing the children’s performance and monitoring technical or physical difficulties during a standardized tutorial on the technical handling of the HoloLens2. The results for each research question are presented and the implications of these results for the use of HMD-AR-devices with children of primary school age in educational settings are discussed.

Study design and procedure In a within-subjects-design, 46 children (27 male, 19 female) aged between 8 and 11 years (M=9,3, SD= 0,9) were individually invited to complete a standardized tutorial on the Microsoft HoloLens2 in a controlled laboratory environment. Before starting the tutorial, the children were interviewed on previous experience with AR-technologies and were introduced to the device and the immersive AR- experience with a standardized demonstration and explanation. During the tutorial, the children performed different actions and interactions with AR-objects that included gesture-based direct interaction (“tap”: directly tapping on objects to select them), gesture-based indirect interaction (“air- tap”: targeting objects from afar and then clicking with fingers to select them), and voice-command interaction (saying a command to select an object) guided by a standardized instruction. Each form of interaction had to be done three times. During the tutorial, the children’s actions and interactions with the AR-objects were recorded by an external camera, as well as by the POV-camera of the HoloLens2 itself. After completing the tutorial, the children were asked to name any perceived physical inconveniences (e. g., pain, vertigo, blurry vision) and any perceived technical difficulties (e. g., the device not reacting to their actions or losing track of spatial position). Data analysis Research question 1: The videos from the external camera and the POV-camera in the HoloLens2 were analyzed regarding the technical performance of the three ways of interaction with the AR-objects. For each of the three interaction methods, the number of attempts for a successful action was counted for each of the three times that the action was performed. The mean value of these three numbers of attempts (metric variable ranging from one to infinity) then served as the measured value of the performance of the child on the respective interaction method. The performance values for the three interaction methods were then statistically compared with an ANOVA for dependent samples. Research question 2: Technical and physical peculiarities were evaluated by the means of qualitative content analysis of the video recordings from the tutorial and of the children’s feedback after the tutorial.

The data acquisition will be finished in February 2021. By now, the present data indicate an equal performance of both, the voice-command and the direct “tap”-interaction, while the “air-tap”- interaction performance is noticeably inferior. Especially the voice-command interaction performing so well is surprising as this is not consistent with previous research results that found speech recognition with children to be a challenge and to not work reliably (Kennedy et al., 2017), not even with the previous model HoloLens1 (Munsinger et al., 2019). These results may indicate an improvement of usability of head-mounted AR-devices with younger children. In terms of technical or physical peculiarities, we cannot provide any valid information at this time as the analyses of videos and feedback have not been conducted yet, but this will be completed by the time of presentation. All presented results serve as an exemplary reference for the general technical performance of current head-mounted AR-technology with children of primary school age and will be discussed regarding the implications on the affordances and limitations of the use of these devices in (primary) educational settings.

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