Auditory hallucinations as primary disorders of syntax: an evolutionary theory of the origins of language.

A theory of the evolutionary origins of language is built around: (1) the notion that language is a sapiens-specific capacity that arose in the speciation event that separated modern Homo sapiens from a prior hominid species, and (2) Broca's concept of asymmetry (subsequently recognised as a "torque" from right frontal to left occipital cortices) as the defining characteristic of the human brain. The four chambers of human association cortex thus created allow the separation of "thought" from the speech output and "meaning" from the speech input, these abstractions representing the associations in the nondominant hemisphere of the motor and sensory phonological representations in the dominant hemisphere. The nuclear symptoms of schizophrenia are conceived as manifestations of the breakdown of the boundaries between these four compartments, and as indicating the necessity of the separation of motor and sensory speech engrams as the basis for the speaker-hearer distinction. They further illustrate a requirement for a "deictic core" to the cerebral organisation of language as Mueller and Buehler proposed. In this sense the nuclear symptoms are disorders of the syntax of universal grammar.