Earlier quoted context omitted.
To most people, "how predictable you are" and "whether you have free will" are almost the same question.
Those people are wrong. Other commenters dealt with that below. RE free will itself, I'm thinking it has more to do with metacognition and general complexity of thoughts. People may have free will, but they're running the same "free will algorithm" - give them the same inputs, and most of the time you'll get the same outputs. A lot of people don't want to consciously accept that, but it's a fact. It's e.g. why econom…
That's not quite how economics work. It's more like, outputs from a given set of inputs can be characterized in a statistical way at scale (which is subtly different from saying that individuals are predictable at scale.) It's not that every person will choose to buy pizza if it's $11.99 but not if it's $12.00, but instead that if you offer pizza for $11.99 you'll generally get between X and Y sales per day, and if you increase that to $12.00 you can expect to lose about Z sales, and you can mess with that curve to try to maximize revenues or whatever.
I would say that what makes "free will" an interesting concept is that it's about how one chooses to prioritize different values -- how they express meaning by their choices. In the sense of a "free will algorithm", it's how you choose to weight different factors in your algorithm. How do you weight comfort, pleasure, stimulation, challenge, avoidance of pain, etc.? How do you weight those things for others? In practical usage, we talk about "free will" when someone makes a choice that surprises us, showing that their value system or their evaluation matrix is different from ours.