Does overlay field of view in head-mounted displays affect spatial memorization?

One of the main targets of criticism of head-mounted displays (HMDs) is the field of view (FOV) size, whether in virtual or augmented reality. This limitation is prominent with optical see-through head-mounted displays (OST-HMD), as those with narrow overlay FOV (OFOV) sizes only provide a small window to view virtual objects. We investigated if restricting this OFOV negatively affects a user's ability to memorize spatial locations in a simulation of a work environment, and consequently, long-term memory transfer to an equivalent scenario in the real world two days later. To find empirical evidence, we conducted a within-subjects experiment with 18 participants performing in three phases with an OST-HMD, simulated on an immersive HMD. For each phase, they viewed the training scenario with a different OFOV size of the augmentable area (30°, 70°, 110° diagonal). Results from recall tests showed that smaller OFOV size did not significantly affect user's performance on both short-term and transfer tests, but HMD data revealed that users rotated their heads less with a 110° OFOV. We also found that proximity of objects to memorize had an interaction effect with smaller OFOV sizes. Our findings could have implications on the design and HMD choices of augmented training.