Collaboration between a human and an autonomous tangible interface can lead to frustration and conflicts of control
We present and validate a solution for sharing the control between the human and the interface.
Our Adaptive collaboration solution is based on two principles
First, the TUI always communicates its intent to take control using minimal non-verbal gestures
Second, the human is always in control, and can accept or reject the TUI's intent to take control
In a controlled lab study, we compared between Adaptive and Non-adaptive collaboration
using an identical tangible interface and task
Our findings show that adaptive collaboration leads to improved teamwork quality
better sense-of-control, and overall more positive perception of the shared-control experience
We used a previously published prototype that we developed at our lab
The original design process started with low fidelity prototypes and continued to high fidelity
We implemented a unique mechanism with 2 motors, one for lean-forward movement
and one for endless rotation movement
We designed various non-verbal gestures by studying the movement of dancers
And then implemented the gestures on the actuated interface
We decided to use an Anagram task to provide a clear shared goal for the collaboration between human and tangible interface
The anagram game consists of four Hebrew letters on a set of four pillars
Both the human and the system can rotate the pillars and construct words at the same time
The system can recognize correct or incorrect words, and can complete words autonomously
Our proposed collaboration behavior for adaptive control is based on prior literature
as well as pilot studies featuring two humans interacting with the actuated interface.
The main insight: that collaboration requires a common non-verbal communication language to resolve conflicts of shared-control
Also pertinent: the need to anticipate the other party's intention, and the need to request help when needed
In addition, we learned which natural gestures participants used as non-verbal common language
and leveraged them in our final gesture design
Based on participants' continuous finger rotation to communicate let's start over - we designed a full rotation of all pillars
Based on finger-pointing towards oneself or towards the other to communicate a desired shift in control
we designed the signal as a gentle lean-forward performed by one of the pillars
We extended the existing prototype with the Adaptive collaboration behavior
The adaptive behavior is based on three aspects
First, prediction of the human's intent
The system sensed whether the user rotated the pillars or not, and measured the duration of inactivity
This enabled prediction of the user's need to maintain control or to release control to the system
Second, communicating the system's intent
When the system assumed the human is interested in releasing the control
it communicated its plans to take the control using a physical signal
The signal was designed as a minimal non-verbal gesture
Prior work shows non-verbal gestures are perceived as social cues
Third, giving the human the choice to maintain or release control
We implemented a sensing procedure allowing the user to accept or reject the system's suggestion to take control
In a controlled study with 24 participants, we compared between Adaptive and Non-adaptive conditions, in a counterbalanced order
The quantitative and qualitative findings show that the Adaptive condition led to better collaboration
The qualitative measures indicated that the Adaptive condition was experienced as fluent team-work
while the Non-adaptive condition was experienced as a frustrating struggle for control
Participants in the Non-adaptive condition said
Participants in the Adaptive condition said
The quantitative analysis of the Godspeed questionnaire revealed that the Adaptive condition
resulted in significantly higher ratings than the non-adaptive condition
To conclude, collaboration between humans and autonomous tangible interfaces can be fluent team-work rather than a frustrating struggle
The adaptive experience was perceived as "encouraging, supportive, and motivating"
while in the non-adaptive condition it was perceived as "annoying, interrupting, and frustrating"
We hope our work can inspire designers of tangible collaboration to add adaptive behavior to their systems
We offer two recommendations: one, that a system should communicate its intent
And two, that the human should remain in control throughout the interaction process
and be able to decide whether they wish to accept or reject the system's help
Our findings show that adaptive behavior can lead to fewer conflicts of control, less frustration, and a better collaboration experience