Breaking Players' expectations: the Role of Non-player Characters' coherence and Consistency

In video games, non-player characters (NPCs) play a pivotal role in shaping players' experiences. The design of these characters, encompassing their appearance and behaviors, can be manipulated in terms of coherence and consistency to maintain players' expectations or, on the contrary, to surprise them. The extent to which NPCs' coherence and consistency influence players' evaluation of them remains to be unveiled. To address this knowledge gap, two experiments were conducted in the context of a military shooter game. Players' evaluations of NPCs' perceived intelligence and believability were measured, as these two dimensions are fundamental to players' adoption of NPCs and subsequent commitment to them. The first experiment investigated the impact of disrupting players' initial expectations on their evaluations of NPCs. The second experiment focused on the influence of NPCs' coherence and consistency on both players' expectations and evaluation of NPCs, using a combination of questionnaires and behavioral and physiological measures. The results of our study show that disrupting players' initial expectations influences their assessment of NPCs, with coherent and consistent design reinforcing expectations and incoherent design challenging them.