The embodied digital divide: how sensorimotor experience shapes touchscreen typing performance and strategy

: This study investigated how divergent sensorimotor experiences interact with task intention to influence touchscreen typing performance, kinematics, and strategy in smartphone users. Building on principles of motor learning and embodied cognition, we compared two generational cohorts: individuals whose sensorimotor development was primarily in the physical world, and those whose development occurred concurrently in both physical and digital environments. Participants typed the same sentences in two tasks: WhatsApp Chat (content generation) and Google Search (content consumption). 3D motion capture measured thumb kinematics; video analysis assessed behavioral metrics including typing time, predictive text use, and errors. Behavioral metrics revealed that the group with early digital exposure demonstrated faster overall typing times. The group with later digital adoption showed significantly greater use of predictive text, especially in WhatsApp, while typing errors did not differ. Kinematic analysis showed the early-digital-exposure group exhibited a higher-vigor motor execution profile and later peak deceleration and velocity, indicative of more ballistic, pre-planned movements. Crucially, Movement Time also exhibited a complex interaction, highlighting context-dependent modulation of motor efficiency. Thumb usage patterns did not show major group or task differences. These findings demonstrate that an individual's sensorimotor history contributes to shaping fine-grained sensorimotor skills. Those with early digital exposure display superior motor efficiency and vigor. In contrast, individuals with later digital adoption, though less kinematically efficient, exhibited remarkable strategic flexibility, adapting motor control and leveraging interface features based on task demands. This underscores how divergent sensorimotor histories contribute to distinct expressions of digital fluency and adaptive strategies in the digital age.