This just occurred to me today, so I am writing this down while it’s fresh. When I talk about the shared mental model space (SMMS), I usually picture it as something like a bunch of circles, one for each individual within a group, and these circles are touching a larger circle that represents the mental models that are shared by all members of the group. It’s not the most accurate diagram, but it will work for this thought experiment. As I was reflecting on the desired properties of a SMMS, I realized that there’s a tension at play.

On one hand, I want my organization’s SMMS to be large enough to allow us to understand each other, to be “on the same page” so to say. At the same time, I am recognizing that a SMMS that perfectly encloses all of the individuals’ mental models is both impossible and undesirable. It is impossible, because in trying to achieve perfect closure, we encounter the paradox of understanding: since everyone’s internal mental model also includes the enclosed models themselves, we rapidly descend into the hall-of-mirrors situation. It is undesirable, because a team where all of the opinions are known and completely understood is only facing inward. There is no new information coming in. So there appears to be a sort of polarity in the size of the shared mental model space – and a tension it embodies.
A SMMS can both work for and against the organization. As it grows, the organization becomes more blind to the externalities. A cult enforces the suffocating breadth of SMMS among its members, since that’s what makes it impervious to change. As SMMS shrinks, the organization stops being an organization. If the diversity of perspectives is high, but there’s no way to share them, we no longer have a team. It’s just a bunch of people milling around.
The weird thing about polarities is that the sweet spot in the middle is elusive. Sitting right in the middle of the tension, it’s more likely to be periodically passed by the team — “OMG, this was amazing! Wait, where did it go?” — rather than having the team settle down in it. Even more annoyingly, diminishing the SMMS decreases the chances of reestablishing it — and large SMMS makes introducing new perspectives impossible. Both extremes are “sticky,” which means once an organization moves past some threshold, only a severe external perturbation can dislodge the state of its SMMS.
So it appears that it really matters how we decide to establish this space where our mental models are shared, and how we garden this space. The thing that becomes more and more evident to me is that if we do so in an unexamined way, we are unlikely to have a sustainable, resilient organization.