Study on the Impact of Situational Explanations and Prior Information Given to Users on Trust and Perceived Intelligence in Autonomous Driving in a Video-based 2x2 Design

In this paper, results from a video-based study on the influence of prior information given to users and explanations situationally given by the vehicle itself on trust and perceived intelligence are presented using a simulated autonomous vehicle in an ambiguous driving situation. A 2x2 between-subjects design is chosen with two independent variables 'prior information' (extended/short) and 'explanations' (yes/no) with users pseudo-randomly assigned to one of the four conditions. Significant results from 189 test persons reveal, that trust depends on how the capabilities of the intelligent vehicle are explained a priori and not on situational explanations, while perceived intelligence is influenced by both variables. Additional interactions of prior information and user gender is noted with respect to perceived intelligence. As one side effect, it is found, that male users felt significantly more safe than female users with also higher ratings of intention to use the vehicle independently of given information and explanations. Another side effect is that situational explanations lead to better ratings of subjective performance, while also here a significant interaction of gender and prior information is noted. Thus, contrary to expectations, a dominant role of continuous situational explanations (Explainable AI) of the intelligent vehicle for increasing trust is not confirmed and the extent of given prior information seems the deciding factor for initial trust building, which is an important aspect for the introduction of new intelligent technology into society. This is remarkable as at the same time perceived intelligence seems to be dependent on both variables. So it appears, that a vehicle being able to explain its actions may well appear more intelligent, but not necessarily appear more trustworthy.