Perception Is All You Need: A Neuroscience Framework for Low Cost Sensorless Gaze in HRI
Organizations: Computing and Software, Faculty of Engineering, McMaster University
Abstract
Gaze-following in child-robot interaction improves attention, recall, and learning, but requires expensive platforms ($30,000+), sensors, algorithms, and raises privacy concerns. We propose a framework that avoids sensors and computation entirely, instead relying on the human visual system's assumption of convexity to produce perceptual gaze-following between a robot and its viewer. Specifically, we motivate sub-dollar cardboard robot design that directly implements the brain's own gaze computation pipeline in reverse, making the viewer's perceptual system the robot's "actuator", with no sensors, no power, and no privacy concerns. We ground this framework in three converging lines of theoretical and empirical neuroscience evidence. Namely, the distributed face processing network that computes gaze direction via the superior temporal sulcus, the high-precision convexity prior that causes the brain to perceive concave faces as convex, and the predictive processing hierarchy in which top-down face knowledge overrides bottom-up depth signals. These mechanisms explain why a concave eye socket with a painted pupil produces the perception of mutual gaze from any viewing angle. We derive design constraints from perceptual science, present a sub-dollar open-template robot with parameterized interchangeable eye inserts, and identify boundary conditions (developmental, clinical, and geometric) that predict where the framework will succeed and where it will fail. If leveraged, two decades of HRI gaze findings become deliverable at population scale.
Figures & tables
| Constraint | Rationale |
| Dark pupil on light iris | The visual system uses a dark-on-light heuristic for gaze computation ( Ricciardelli et al., 2000 ) . Reversing contrast impairs or eliminates the gaze percept. |
| Face-like configuration | The convexity prior is face-specific ( Papathomas and Bono, 2004 ; Hill and Johnston, 2007 ) . Two eyes in a face-like arrangement with a protruding snout maximize prior engagement. An isolated concave disc without facial context produces a weaker illusion. |
| Upright orientation | The illusion is disrupted by inversion ( Papathomas and Bono, 2004 ) . The robot must be presented upright. |
| Viewing distance m | At close range, binocular disparity provides high-precision depth information that can override the prior. The illusion is strongest where binocular cues are weak. |
| Familiar lighting | The illusion is strengthened by shading from above and weakened by unusual lighting that disrupts expected illumination gradients ( Hill and Johnston, 2007 ) . |
Human-Robot Interaction
Human-robot interaction studies how people and robots communicate, coordinate, and safely work or live together.
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