  In recent years, various service robots have been introduced in stores as
recommendation systems. Previous studies attempted to increase the influence of
these robots by improving their social acceptance and trust. However, when such
service robots recommend a product to customers in real environments, the
effect on the customers is influenced not only by the robot itself, but also by
the social influence of the surrounding people such as store clerks. Therefore,
leveraging the social influence of the clerks may increase the influence of the
robots on the customers. Hence, we compared the influence of robots with and
without collaborative customer service between the robots and clerks in two
bakery stores. The experimental results showed that collaborative customer
service increased the purchase rate of the recommended bread and improved the
impression regarding the robot and store experience of the customers. Because
the results also showed that the workload required for the clerks to
collaborate with the robot was not high, this study suggests that all stores
with service robots may show high effectiveness in introducing collaborative
customer service.
