Imagine that you've written a short to-do list in your notes app, driven to the shops, and then reopened your notes.

You'll subconsciously (and very quickly) go through a process of evaluating if the list is the same as what you were just looking at.

And your brain takes a shortcut, by trying to match patterns.

i.e., in the above example, even without reading the actual words, you could quickly identify that they're very likely to be the same list.

The pattern of the words (e.g., their sizing, spacing, number of items) are very similar.

But now try that same exercise with the following:

It's much harder, because the order of the items has changed. Your brain recognises that the pattern has broken (the shape of the content), and now you need to engage more in the task.