What does the little circle next to each officer portrait mean in Sunless Skies?

What does the little circle next to each officer portrait mean in Sunless Skies?

After recruiting an officer and opening the Officers interface, each officer appears as a portrait. Clicking on their portrait lets you interact with them.

At the bottom right of each portrait there is a small circle. Clicking in the circle causes the officer hat icon to appear and disappear. What does this hat mean? Multiple officers at different stations can have it enabled at the same time.

The hat means they are assigned to that position. Officers only give their bonuses when assigned, so make sure you have them working. If they aren't, they're just fancy passengers.

You can only change which officers are assigned to each position while in port.