Why is the S&P, DOW, and Nasdaq all moving up and down at the exact same time....

I'm honestly trying to understand. I'd assume there would be some variance in different indexes and different movements at different times, but over the last month its almost identical and within the last week is pretty much identical, with blimps up and down all at the same time......

Is it truly is just automated at this point? I knew it happened, but thought some of it was blown out of proportion.