Evolutionary Theories in the Social Sciences

September 17, 2004

Important New Evidence on Language Development. Science magazine (Vol. 305, pp. 1779-1782) published the analysis of an amazing natural experiment in Nicaragua where deaf children created a new sign language.

Summary: Although the findings are consistent with both directions of effect in the evolution of learners and languages, they are at odds with accounts in which such attributes evolved externally, were passed from generation to generation solely through cultural transmission, and were never reflected in the nature of the learning mechanism . In studies of mature languages, the potential imprint of the learning mechanism is redundant with, and hence experimentally obscured by, preexisting language structure. But the rapid restructuring of Nicaraguan Sign Language as it is passed down through successive cohorts of learners shows that even where discreteness and hierarchical combination are absent from the language environment, human learning abilities are capable of creating them anew.

Electronic Version and Supporting Documents: http://www.sciencemag.org/cgi/content/full/305/5691/1779/DC1