  Search systems on the Web rely on user input to generate relevant results.
Since early information retrieval systems, users are trained to issue keyword
searches and adapt to the language of the system. Recent research has shown
that users often withhold detailed information about their initial information
need, although they are able to express it in natural language. We therefore
conduct a user study (N = 139) to investigate how four different design
variants of search interfaces can encourage the user to reveal more
information. Our results show that a chatbot-inspired search interface can
increase the number of mentioned product attributes by 84% and promote natural
language formulations by 139% in comparison to a standard search bar interface.
