## 1 Introduction
### Robots for the Elderly and Acceptance Issue  
The expected growth in the population of elderly individuals has influenced researchers to design innovative solutions in the field of eldercare including robots. Assistive Human-Robot Interaction involves robots that are designed to aid individuals through physical, social, or cognitive assistance [6]. Specifically, Socially Assistive Robots are designed to help and address social needs through interactions of a specific category of users, e.g., autistic children or elderly individuals. A very famous example in the final category corresponds to Paro, namely a touch-sensitive seal robot that produces positive effects for dementia patients, such as mood improvement and a calming effect, in several experiments [7].  
In the field of eldercare, a newer technology trend involves aiding elderly individuals to remain at home and live independently to the maximum possible extent. Several projects focus on ambient assisted living [8] and follow the same basic approach wherein a house becomes a smart environment that is full of sensors that provide services such as indoor user localisation, activity and event recognition, user health status assessment, etc. and a service robot is integrated with other types of assistive devices by a cloud [9]. Such robot is an embodied interface of the smart systems for net-living environment. By considering human factors, this robot aims to help people at home or in a nursing home and to contribute to enhancement of quality of life.  
The robot in these cases typically corresponds to a wheel based mobile platform with a touch screen for a user interface--e.g., Kompai in the Domeo project [10], Care-O-bot in the Accompany Project [11] and ScitosG3 in the Companionable Project [12]--or with a video for telepresence--e.g., the Giraff robot in the Excite Project [13]. The shape of the service robot is related to its tasks, e.g., to provide telepresence services to enable communication with elderly individuals or with medical staff to perform basic actions such as handling an object or to provide reminders about appointments. Cloud technology is an important solution that must be considered because it makes a robot cheaper and more efficient and provides opportunities to store additional information and to access knowledge provided by other sensors around the house.  
In a manner similar to any commercial product, the success of a robot mainly depends on the level of acceptability perceived by the users. In the case in the present study, target users correspond to elderly individuals who may be more vulnerable and definitely possess individual necessities that should be addressed. An individual accepts and uses a certain tool if the following requirements are met: the individual possesses a motivation to use it, he/she considers it easy to use, and he/she feels physically and psychologically comfortable using the same. Therefore, it is important to initially understand the motivations of elderly individuals to accept or reject a new technology. Questionnaires are usually used to quantitatively evaluate users' response during experiments. For example, the Almere Model [14] was specifically designed to test the acceptance of socially assistive robots by older adults in a care home and was then successfully used in [15].