Research
Our sociable robot system addresses a main shortcoming of existing weight loss programs, that of long-term adherence.  Combining what we have learned during several years of research in human-robot interaction with current weight loss and weight management techniques, we have constructed a system that allows people to manage weight-related data and interact with a robotic coach.

A relationship model has been developed to appropriately create and manage the relationship between the coach and the user. Based on what is known about human relationships, human-robot interaction, and relationships with agents, the model allows the user's interactions with the coach to evolve over time, allowing the system to establish a pattern of engagement that attempts to keep the user using the system, and therefore maintaining their weight loss and maintenance behaviors, longer than they otherwise would.

Much like a human coach, the robotic coach attempts to become a part of the person's social support network. By integrating into this existing network, this system can take advantage of the known benefits of social support in weight loss and weight maintenance. By helping a user keep track of data relevant to their weight loss program, the user has the option of sharing the data with family, friends, or caregivers as a way to gain their support in encouraging progress.

The coach offers feedback on recent behavior and makes recommendations for near-term behavior. The feedback is based on comparing recent diet-related behavior, such as calories consumed and exercise performed, with goals set by the user. Recommendations come from general information on diet, nutrition, and exercise and are tailored to the individual based on the current stage of the relationship between the coach and the user.

The system maintains a database that keeps track of interactions with the user, information gathered from the user, and goals set by the user. This is used in the relationship model and for the feedback to determine how each interaction should occur.

The sociable robot system consists of an interactive robot coach and a computer that maintains the necessary information. The robot is able to orient its head and eyes to perform simple non-verbal communication cues such as mutual gaze and joint attention. It also has a synthesized voice in addition to displaying text on a screen.  Earlier work we conducted in human-robot interaction has shown that a robot can be more engaging than a character on the screen, which leads to our using a physical robot in this system rather than an agent on a PDA, phone, or computer. Other pieces of the system will allow automation and simplification of the system for users.

In a controlled long-term evaluation study, we compared the robotic coach to a standalone desktop computer running the same software and to a traditional paper log. A current challenge in weight management is not losing weight but rather in getting individuals to keep off weight that is lost. The results of our study show that participants track their calorie consumption and exercise for
nearly twice as long when using the robot than with the other two interventions and develop
a closer relationship with the robot. Both of these are indicators of longer-term success at weight loss and maintenance.

The results from our study support the following hypotheses:
  • Participants interacting with the robot will use the system for an overall longer period of time than participants who have a computer or a paper log.

  • Participants interacting with the robot will rate the system higher on regular responses to the short version of the working alliance inventory (WAI-SF) than participants who have a computer.

  • Participants interacting with the robot will rate the system higher on responses to the full version of the working alliance inventory (WAI) administered at the end of the experiment than participants who have a computer or participants using paper logs.

  • Participants interacting with the robot will rate the system higher on responses to a scale of trust administered at the end of the experiment than participants who have a computer or participants using paper logs.

  • Participants interacting with the robot will rate the system higher on responses to a scale of engagement administered at the end of the experiment than participants who have a computer or participants using paper logs.

  • Participants interacting with the robot will rate the system higher on responses to a scale of reliability administered at the end of the experiment than participants who have a computer or participants using paper logs.

  • Participants interacting with the robot will have a closer bond by the end of the experiment than participants who have a computer or participants using paper logs.

  • There will be no difference in the amount of weight lost across all three groups at the end of the six week study period.
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