Ageing, Digital Literacy, and Interaction Modality in Immersive Virtual Reality: Psychomotor Performance, Cognitive Flexibility, and Their Associations with Processing Speed

Extended reality (XR) increasingly supports training and cognitive assessment, yet the age sensitivity of its interaction techniques is unclear. This study examined age, digital literacy, and interaction modality as correlates of psychomotor and cognitive-flexibility performance in immersive virtual reality (VR). Two hundred and two adults (19–90 years) completed a five-mode Fitts’ law task (eye gaze, head gaze, controller ray-casting, virtual finger, and controller direct touch), the Trail Making Test in VR (TMT-VR), and a digital-literacy questionnaire. Age was associated with slower task times across modes, but controller direct touch carried the steepest relative age gradient while remaining among the fastest in absolute terms; technique altered relative age sensitivity without determining absolute efficiency. Higher digital literacy was associated with faster TMT-VR completion but not Fitts’ law task times. In the planned analyses, a Fitts’ law derived speed score predicted TMT-VR performance beyond age and, in a statistical decomposition, partly accounted for its age association, consistent with shared processing-speed variance. A post hoc exploratory full-battery extension confined the Fitts’ law score association with completion-time and error-adjusted-time indices and the digital-literacy association to error-adjusted-time indices, not wrong-target errors, mean selection distance, or relative Part B indices. Age-inclusive XR assessment should standardise interaction modality, evaluate rather than exclude mid-air direct selection, and interpret cognitive scores alongside digital literacy and psychomotor speed.