I'm curious to hear this about what someone may be doing alone that strictly isn't "social interaction". Normally I would think that they are doing something that only requires one active participant -- maybe reading a book, watching shows, browsing the Internet, even something like taking a bath and enjoying a candle.

I might consider each of these to actually involve other people outside of that moment who you are experiencing asynchronously. The media is written, the candle is made, they were bought from a store. Not sure if I would count the bath water yet, but there was some work done before even laying the pipe and collecting the materials.

Unless you are literally making everything from raw natural materials, other people are deeply involved in our lives and I don't think we appreciate that enough about society. So while you would be at least arm's distance from anybody in your room, I don't think you are ever really alone.