I. INTRODUCTION
Individuals accumulate years of experience observing both their own and others’ actions in manipulating fluids. This learned behavior equipped us with an internal physics engine, allowing us to anticipate the outcome of a pour and identify and change necessary adjustments during the pouring process to prevent spills [1], [2]. However, it remains uncertain whether individuals can accurately predict the outcomes when a robot is manipulating fluids, particularly when they lack a precise mental model of the robot’s capabilities upon initial encounter. Users with an assistive robotic arm for pouring a drink may find themselves at risk of spills due to unfamiliarity with the robot’s behavior.