But, "sentience" or "consciousness" isn't defined as "decision-making."

I think at its root, it is. IMHO biological consciousness can be observed along a spectrum that goes from a simple one-celled paramecium searching for food, to an ant, to a bird, to a chimpanzee, to us. But when I say 'decision-making' I don't necessarily mean on the level of what motivates the organism as a whole. It also can be part of the processes that distinguish a tree from the space behind it, to recognizing the face of someone you know from a stranger. These are biological algorithms that enable us to construct a complex consciousness.

Watson beat Ken Jennings at Jeopardy. This was a display of artificial intelligence, and also a type of consciousness. Watson is artificial, but it was able to parse answers and retrieve facts and construct the correct questions which made it able to win the game. Ken Jennings, although he has many other capacities, was doing a very similar thing. In fact, if you gave him some very specific neural injuries, you could experimentally display it. Mess with Broca's area, and he could retrieve the information into his inner dialog, but could no longer parse it into language (a lobotomy-like injury could make him emotionally flat). Watson's missteps seem so weird and lacking thought, but that is due to the fact that it had no ability to create or draw on cultural knowledge or any type of experiential knowledge. Watson's knowledge was a very specific type, but it was enough to win. I don't know if there wasn't a stochastic element to Watson's decision-making, but some artificial intelligences do employ it. Many also employ machine learning, like a translator learning your accent. At any rate, sophisticated programs that can evolve based on input are going to be integrated together to make some dynamic artificial intelligences. Imagine 20 Watsons that have a range of specialties working in parallel, but together as one entity. That's much how our brain works.

A mouse and my brain are very similar on the cellular level, but on the macro level, our consciousnesses are quite different. Watson is a cricket. But soon we will start integrating many Watsons together into another type of architecture. It won't be too long before we have a Watson mouse. And then, a Watson Watson.