Humans Use Predictive Gaze Strategies to Target Waypoints for Steering

Abstract

A major unresolved question in understanding visually guided locomotion in humans is whether actions are driven solely by the immediately available optical information (model-free online control mechanisms), or whether internal models have a role in anticipating the future path. We designed two experiments to investigate this issue, measuring spontaneous gaze behaviour while steering, and predictive gaze behaviour when future path information was withheld. In Experiment 1 participants (N = 15) steered along a winding path with rich optic flow: gaze patterns were consistent with tracking waypoints on the future path 1–3 s ahead. In Experiment 2, participants (N = 12) followed a path presented only in the form of visual waypoints located on an otherwise featureless ground plane. New waypoints appeared periodically every 0.75 s and predictably 2 s ahead, except in 25% of the cases the waypoint at the expected location was not displayed. In these cases, there were always other visible waypoints for the participant to fixate, yet participants continued to make saccades to the empty, but predictable, waypoint locations (in line with internal models of the future path guiding gaze fixations). This would not be expected based upon existing model-free online steering control models, and strongly points to a need for models of steering control to include mechanisms for predictive gaze control that support anticipatory path following behaviours.

Theoretical interpretation of drivers’ gaze strategy influenced by optical flow

“…In contrast, the Future Path Point (FP) is an arbitrary single point on the ideal future path for an individual driver on the road; for instance, the center of the path or corner-cutting path 11 . This gaze behavior has also been observed in various studies 4 , 11 – 19 . The TP is a behavioral concept in which the driver’s gaze point is uniquely determined by the environment and vehicle condition; in other words, the individual characteristics of the driver are not included.…”

“…Humans use their visual systems to guide their locomotor control; in the driving context, drivers take advantage of visual information to safely operate their vehicles 1 , 2 . The typical pattern of gaze in driving is characterized as the driver looking to where they want to go and steering towards that point 3 , 4 . Thus, revealing driver gaze point during driving is a key factor in a holistic understanding of driving behavior because driver gaze is the first sensory information process in driving.…”

Movements of the eyes and hands are coordinated by a common predictive strategy

“…This study provides valuable new insights into the role of prediction in naturalistic control of gaze and hand movements, and builds upon a growing body of literature suggesting that, although predictive control strategies may not be readily apparent in the analysis of navigation or effector placement (Zhao & Warren 2014), predictive mechanisms are fundamentally involved in the control of eye movements in visually guided action in natural or naturalistic contexts Diaz, Cooper, Rothkopf, et al, 2013;Land & McLeod, 2000;Mann et al, 2013;McKinney, Chajka, & Hayhoe, 2008;Tuhkanen et al, 2019). What is less clear, however, is how predictive gaze control is related to predictive control strategies for controlling the effector (e.g., the paddle).…”

Looking at the Road When Driving Around Bends: Influence of Vehicle Automation and Speed

“…However, it should be noted that the range of speeds used in the study (60–90 km/h) was not very large, and as such would not substantially change the eccentricity of GF glances (cf. Tuhkanen et al, 2019). Larger differences in GF gaze distribution might be observed at very high speeds, which might in turn have an effect on gaze polling.…”