Using individual differences to understand saccade-pursuit interactions

Eye-tracking and psychophyisical data for 8 different experiments all performed by the same observers. Experiments are focused on measuring saccadic and pursuit eye movements performance in isolation as well as their coordination in response to position- and velocity-related information.

Research on saccadic and pursuit eye movements already made great contributions to our understanding of sensory processing and human behavior. However, studies often have focused on average behavior of only one specific type of eye movement in a specific task. By leveraging individual differences of 50 observers across a unique combination of different tasks, we demonstrate that critical links and variations in the control of oculomotor behavior are missed by focusing on average behavior across participants of isolated eye movements. We observed that saccade and pursuit behavior across tasks are correlated, but only when tested with matched sensory information: accuracy of saccades to moving targets is correlated with pursuit gain, but not accuracy of saccades to stationary targets. Within the same task, the coordination of saccadic and pursuit eye movements is tailored to the strengths of the individual: observers with more accurate saccades to moving targets use them more frequently to catch-up with moving targets. Our findings demonstrate that individual variations in sensorimotor behavior are more than just measurement noise and questions previous results and interpretations based on the comparison of saccadic and pursuit eye movements with different sensory input.