Even with its engines on hard reverse, a supertanker can take one mile to come to a stop. This property of mass—resistance to a change in motion—is inertia. In business, inertia is an organization’s unwillingness or inability to adapt to changing circumstances. Even with change programs running at full throttle, it can take many years to alter a large company’s basic functioning.

Here’s how each essentially functions:

• The emotion default: we tend to respond to feelings rather than reasons and fact.

• The ego default: we tend to react to anything that threatens our sense of self-worth or our position in a group hierarchy.

• The social default: we tend to conform to the norms of our larger social group.

• The inertia default: we’re habit forming and comfort seeking. We tend to resist change, and prefer ideas, processes, and environments that are familiar.

There are no hard edges between defaults; they often bleed into one another. Each on their own is enough to cause unforced errors, but when they act together things quickly go from bad to worse.

The physicist Leonard Mlodinow sums it up this way: “Once our minds are set in a direction, they tend to continue in that direction unless acted upon by some outside force.” This cognitive inertia is why changing our minds is hard.

Inertia keeps us doing things that don’t get us what we want. It operates in our subconscious largely undetected until its effects are too hard to counter.

It’s easy to underestimate the role ease plays in decision-making. Since behaviour follows the path of least resistance, a surprisingly successful approach is to add friction where you find yourself doing things you don’t want to do.