So what really is user experience? An experimental study of user needs and emotional responses as underlying constructs.

This driving simulator study extended knowledge on user experience using a strategy to mitigate distraction resulting from the use of in-vehicle information systems (IVISs). It examined the impact of system restrictions on users' needs, emotions and consequences of users' experience in terms of psychological reactance. In a repeated measures design, we asked 53 participants to perform secondary tasks with an IVIS while driving. Three versions of the system varied with respect to the number of operable functionalities. The more functionalities that were disabled while driving, the more negatively users rated the systems. Multilevel regression analyses of at least n = 155 data points revealed that drivers' need fulfilment predicted their emotions. Reactance depended on users' need fulfilment and emotions. Experienced autonomy mediated the relation between functional limitations and reactance. When developing interactive systems, one should focus on needs and be aware of potential unwanted consequences such as psychological reactance. Practitioner Summary: This driving simulator study highlights the importance of considering need fulfilment and users' emotions when developing an interactive system that provides high user experience. System restrictions could have negative consequences as users might show psychological reactance.