# Collaborative Use of a Shared System Interface:
## 3 Hypothesis Development
### Dyad Gaze Convergence and Its Impact  
In order to assess the predictive validity of the proposed GC index, we developed a model to examine salient associations with GC in the context of a user dyad collaborating simultaneously on a shared system interface. As gaze convergence is the focus of the present paper, our model is developed in the context of tasks performed jointly using a shared system interface, with the users having the same objective and focus. Figure 2 depicts the research model.  
User cognition has been frequently investigated in the IS field and has been referred to as what occupies individual's mind and that s/he is aware of or not while using a system [26; 27]. Cognitive load has been a prominent construct of cognition studied in the HCI and IS disciplines, considered an indicator of efficient use of a system [28; 29]. System user cognitive load has been referred to as the extent to which mental resources are employed by users to encode, activate, store, and manipulate data or information as they use a system [29; 30]. The present study adopts this conceptual definition in the context of user dyads collaborating simultaneously on a shared system interface. Cognitive load at dyad level results not only from each individual mind alone but also from interactions between team members, that is, it also happens socially [31]. Users process information not only from the system interface but also the other dyad member. In the context of multiple users, some level of individual effort is needed in order to reach common objectives. Moreover, individual efforts have to be coordinated and aligned to ease collective task achievement [32]. Yet, the effort required for coordination could conceivably be eased when the dyad members share mental models [33] of the system interface they use together. A user's mental model within any time range may develop from how and where he or she looks at the system interface. Thus, mental model is a mechanism through which the user generates descriptions of system purpose and visual form. This permits comprehension of system functions and observed system states, and prediction of future system states [33]. Consequently, when dyad members working together in real-time on a shared visual interface do not look at the same regions in the shared interface, they may not share the same mental model at specific moments, consequently requiring more cognitive resources to communicate and coordinate actions. Thus, we could hypothesize that the more users look at the same regions on the visual interface the less cognitive resources they will need to collaborate. Moreover, two collaborating users looking at the same locations are likely to perform better, as they would be able to better coordinate their interaction. Past research suggests that looking at the same visual objects in a system interface reduces miscoordination incidents, hence improving dyad coordination (e.g., [PERSON] et al. [16]; [PERSON] et al. [34]). Yet, coordinated efforts facilitate the achievement of collective task, increasing team performance [32; 35; 36]. Hence, we make the following hypotheses (H).  
**H:**_Dyad GC will be negatively associated with dyad cognitive load_.  
Figure 2: Model for predictive validity of dyad gaze convergence.  
**H2:**_Dyad GC will be positively associated with dyad task performance._