An Empirical Comparison of Task Sequences for Immersive Virtual Environments

Abstract

System control - the issuing of commands - is a critical, but largely unexplored task in 3D user interfaces (3DUIs) for immersive virtual environments (IVEs). The task sequence (the order of operations in a system control task) is an important aspect of the design of a system control interface (SCI), because it affects the way the user must think about accomplishing the task. Most command line interfaces are based on the action-object task sequence (e.g. "rm foo.txt"). Most graphical user interfaces (GUIs) are based on the object-action task sequence (e.g. click on an icon then select "delete" from a pop-up menu). An SCI for an IVE should be transparent and induce minimal cognitive load, but it is not clear which task sequences support this goal. We designed an experiment using an interior design application context to determine the cognitive loads induced by various task sequences in IVEs. By subtracting the expected time for a user to complete the task from the total time, we have estimated the cognitive time, dependent only on task sequence. Our experiment showed that task sequence has a significant effect on the cognitive loads induced in IVEs. The object-action sequence and similar task sequences induce smaller cognitive loads than those induced by the action-object sequence. These results can be used to create guidelines for creating 3DUIs for IVEs