Dan Sperber (2000) Metarepresentations in an evolutionary perspective. In D. Sperber (ed.), Metarepresentations: A Multidisciplinary Perspective. (Oxford University Press), 117-137.

“Just as bats are unique in their ability to use echolocation, so are humans unique in their ability to use metarepresentations. Other primates may have some rather rudimentary metarepresentational capacities. We humans are massive users of metarepresentations, and of quite complex ones at that…”