Evolution of affective and linguistic disambiguation under social eavesdropping pressures.

Contradicting new dual-pathway models of language evolution, cortico-striatal-thalamic circuitry disambiguate uncertainties in affective prosody and propositional linguistic content of language production and comprehension, predictably setting limits on useful complexity of articulate phonic and/or signed speech. Such limits likely evolved to ensure public information is discriminated by intended communicants and safeguarded against the ecological pressures of social eavesdropping within and across phylogenetic boundaries.