"Can playful deception be a component of the human-robot interaction design?"
Playful deception, a common feature in human social interactions, remains underexplored in Human-Robot Interaction (HRI). Inspired by the Turkish Ice Cream (TIC) vendor routine, we investigate how bounded, culturally familiar forms of deception influence user trust, enjoyment, and engagement during robotic handovers. We design a robotic manipulator equipped with a custom end-effector and implement five TIC-inspired trick policies that deceptively delay the handover of an ice cream-shaped object. Through a mixed-design user study with 91 participants, we evaluate the effects of playful deception and interaction duration on user experience. Results reveal that TIC-inspired deception significantly enhances enjoyment and engagement, though reduces perceived safety and trust, suggesting a structured trade-off across the multi-dimensional aspects. Our findings demonstrate that playful deception can be a valuable design strategy for interactive robots in entertainment and engagement-focused contexts, while underscoring the importance of deliberate consideration of its complex trade-offs. You can find more information, including demonstration videos, on https://hyeonseong-kim98.github.io/turkish-ice-cream-robot/.
The Turkish Ice Cream (TIC) robot system overview.
Magnetic attachment ensures a seamless and safe interaction.
To mimic the Turkish ice cream (TIC) vendor's behavior, we designed a rod-like end-effector equipped on the robotic manipulator. The additional motor enables rapid, continuous twisting rotations, which are difficult to achieve with the manipulator’s built-in motors. The 55 cm rod not only reproduces the vendor’s characteristic tricky motions but also amplifies the cone’s displacement, helping it evade the user’s grasp. The magnetic attachments ensure a seamless retrieval of the cone and safety in an unintentional collision case.
Overview of the five trick policies.
Inspired by the TIC vendor's behavior, the five trick policies were designed, including bouncing, twisting, large arc, continuous arc, and dancing. Each policy has the characteristics of the TIC routine, which are extracted by observation analysis of the online videos of the human TIC vendor. The robot executes the trick policies sequentially, playfully confusing the user while adhering to the predefined interaction duration for each policy.
Straight Handover (SH)
Depcetive Handover (DH)
We conducted a user study with 91 participants to evaluate the effect of the playful Turkish ice cream-style deceptive handover (DH) on the user experience, compared to the straight handover (SH). The participants experienced both of the handover scenarios in a randomized order.
DH Short
DH Medium
DH Long
In addition, we tested how the interactivity duration influences the user experience in the deceptive handover scenario. We set the interactivity duration to short, medium, and long. Short duration employed half the time/iteration of the medium duration, and long duration employed twice the medium duration. The participants randomly experienced one of the three interactivity duration in the DH scenario.
The first-person view video captured during the deceptive handovers in the user study.
The results show that DH was perceived as more deceptive than SH, while increasing enjoyment-related outcomes (pleasure, challenge, engagement) and competence, but reducing trust, safety, and self-competence. The three interaction duration conditions of DH followed a similar pattern. The multi-dimensional analysis reveals a potential role of playful deception in the human-robot interaction design, showing its trade-offs, though it should be used with caution in safety-critical applications.