Three-dimensional (3D) stimuli are always better than two-dimensional (2D) multi-tasking? A high cognitive load in...

The objective of this study is to investigate the whether multi-tasking performance in (three-dimensional) 3D aid or impede cognition compare to (two-dimensional) 2D environments, as reflected by cognitive load. Specifically, we aim to examine the mechanism of multi-tasking under 3D (virtual reality [VR]) and 2D (PC monitor) conditions using the widely used Multi-Attribute Task Battery (MATB) II paradigm.

The MATB-II sub-tasks, namely "Tracking" and "System Monitoring," were conducted with varying task demands in both 3D conditions (Tracking Far - System Monitoring Near [TF-SN], Tracking Near - System Monitoring Far [TN-SF]) and a 2D condition with no depth perception (No Depth [ND]). Participants' cognitive load was assessed using subjective reporting (NASA-TLX) and physiological measure (root mean square of successive difference (RMSSD) of heart rate variability (HRV)).

The study found that performance was significantly better in the ND condition compared to the TF-SN and TN-SF conditions. Furthermore, higher NASA-TLX scores and lower RMSSD values were observed in the TF-SN and TN-SN conditions compared to the ND condition, providing additional support for the overall findings of the MATB-II paradigm.

These findings suggest that processing multiple tasks in different depth planes may lead to poorer performance and increased subjective and physiological cognitive load.