Precise temporal and spatial alignment is critical in collaborative Augmented Reality (AR) where users rely on shared visual information to coordinate actions. System latency and object misalignment can disrupt communication, reduce task efficiency, and negatively impact the overall user experience. While previous research has primarily focused on individual AR interactions, the impact of these inconsistencies on collaboration remains underexplored. This article investigates how user experience and task load are affected by object misalignment and time delay in a shared AR space. To examine these factors, we conducted an experiment with 32 participants, organized into 16 pairs, who collaboratively completed a spatial placement task. Within each condition, both participants alternated roles, taking turns as the leader—providing verbal placement instructions—and the builder—executing the placement. Six conditions were tested, manipulating object alignment (perfectly aligned vs. randomly misaligned) and time delay (0s, 0.1s, 0.4s). The misalignment was applied randomly to each virtual object with a shift of ±20 cm on every axis to create a clear distinction in spatial perception. User experience and task load were assessed to evaluate how these factors influence collaboration and interaction in AR environments. Results showed that spatial misalignment significantly increased perceived workload (NASA-TLX) and lowered user ratings in Pragmatic quality and Attractiveness (UEQ), while time delay had a more limited effect. These findings highlight the critical role of spatial accuracy in maintaining collaboration quality in AR.

The collaboration in co-located shared environments has sparked an increased interest in immersive technologies, including Augmented Reality (AR). Since research in this field has primarily focused on individual user experiences in AR, the collaborative aspects within shared AR spaces remain less explored, and fewer studies can provide guidelines for designing this type of experience. This article investigates how the user experience in a collaborative shared AR space is affected by divergent perceptions of virtual objects and the effects of positional synchrony and avatars. For this purpose, we developed an AR app and used two distinct experimental conditions to study the influencing factors. Forty-eight participants, organized into 24 pairs, participated in the experiment and jointly interacted with shared virtual objects. Results indicate that divergent perceptions of virtual objects did not directly influence communication and collaboration dynamics. Conversely, positional synchrony emerged as a critical factor, significantly enhancing the quality of the collaborative experience. On the contrary, while not negligible, avatars played a relatively less pronounced role in influencing these dynamics. These findings can potentially offer valuable practical insights, guiding the development of future collaborative AR/VR environments.