For sure, this isn't my favorite study mostly due to the sample size. I do think however, this may be one of the most relevant studies to answer or at least offer some understanding to OP's question. Personally I find anything having to do with societal conditioning vs. what our bodies actually need super fascinating.

There are other sources but there was this study done on circadian rhythm. It was conducted in a cave and the findings pointed to humans (or at least the one in this experiment) having closer to a 48 hour day when devoid of clocks ot sunlight. source