Highly speculatively, bicameral mind theory argues for an additional, and cultural rather than genetic, shift from selfless to self-perceiving forms of human cognition and behavior very late in human history, in the Bronze Age. This is based on a literary analysis of Bronze Age texts which claims to show the first appearances of the concept of self around this time, replacing the voices of gods as the primary form of recorded human cognition. This non-mainstream theory is not widely accepted but does receive serious academic interest from time to time.