Error messages are frequent in interactions with Conversational User Interfaces (CUI). Smart speakers respond to about every third user request with an error message. Errors can heavily affect user experience (UX) in interaction with CUI. However, there is limited research on how error responses should be formulated. In this paper, we present a system to study how people classify different categories (acknowledgement of user sentiment, acknowledgement of error and apology) of error messages, and evaluate peoples' preference of error responses with clear categories. The results indicate that if an error response has only one element (i.e. neutral acknowledgement of error, apology or sentiment), responses that acknowledge errors neutrally are preferred by participants. Moreover, we find that when interviewed, participants like error messages to include an apology, an explanation of what went wrong, and a suggestion how to fix the problem in addition to a neutral acknowledgement of an error. Our study has two main contributions: (1) our results inform about the design of error messages and (2) we present a framework for error response categorization and validation.

Psychological reactance is well known in psychology and marketing, but has not yet been adopted in HCI-research. The authors aim at assessing the benefit of measuring psychological reactance in the context of usability and user experience evaluation in a HCI context. To date, there are no tools that are designed to evaluate psychological reactance in the context of HCI. We used an established questionnaire from personality research for an exploratory factor analysis to test, if the concept can be applied to HCI. A between-subjects study was performed that compared effects of self-adaptive vs. user-adaptable systems on users' psychological reactance while interacting with a spoken dialogue system. Results show that interaction with self-adaptive systems can increase psychological reactance, compared to interaction with user-adaptable systems. It is argued, that the concept of psychological reactance is especially relevant for HCI with regard to smart services and assistants like Apple's Siri.

A central requirement for the use of artificial intelligence (AI) in medicine is its explainability, i. e., the provision of addressee-oriented information about its functioning. This leads to the question of how socially adequate explainability can be designed. To identify evaluation factors, we interviewed healthcare stakeholders about two scenarios: diagnostics and documentation. The scenarios vary the influence that an AI system has on decision-making through the interaction design and the amount of data processed. We present key evaluation factors for explainability at the interactional and procedural levels. Explainability must not interfere situationally in the doctor-patient conversation and question the professional role. At the same time, explainability functionally legitimizes an AI system as a second opinion and is central to building trust. A virtual embodiment of the AI system is advantageous for language-based explanations

Four of the nine big Technical Universities in Germany, together with Chalmers University of Technology in Sweden, have developed a new Massive Open Online Course (MOOC) on the subject of Communication Acoustics. The idea is to foster education on the late Bachelor or early Master level by joining the expertise available at individual universities and by creating an online course offered both to local as well as remote students. The course started in winter term 2016 and is hosted on the EdX platform. It is offered in English language and roughly divided into two parts: The first part covers basics on acoustics, signal processing, human hearing, speech production, as well as electroacoustics and psychoacoustics. The second part introduces selected applications, such as sound recording and reproduction, sound fields and room acoustics, binaural technology, speech technology, as well as product sound design. The course material consists of explanatory videos and text as well as audiovisual material, exercises, and self-assessments. The final examination takes place as a written or online exam, with physical presence at the contributing sites. The talk will provide insights into the experiences we made, and illustrates how we overcame the obstacles inherent to cross-university education.