“Our argument in the book is that our consciousness is fundamentally collective first, and that individual consciousness has been overly focused upon because our individual consciousness is so much more vivid than our collective consciousness.”
If there is a “collective consciousness” it came after our indiviual consciousness. Self indentification comes first, followed by that self being part of groups outside our self.
That said, the big problem is that no one knows what consciousness is--collective or individual. All we have are a bunch of hypotheses.
And then add on top of that the idea that 99% (very roughly) of the human mental state is thought to be "subconscious" and we have a really sticky definitional problem.