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Wednesday, December 31, 2008

Theory of Mind I: Feral Children & Language Development

The human mind is quite robust. We can compensate for the loss of any sense and learn to behave normally. People who cannot see or cannot hear from birth can perfectly graduate with advanced academic degrees, provided they are afforded the necessary help. The brain reorganizes. Cortical regions deprived of dominant sensory input may be recruited in the processing of information of other sensory modalities. Detailed reviews of scientific studies examining the neural basis of such reorganization can be found in the book entitled "Blindness and Brain Plasticity in Navigation and Object Perception."

However, if we are deprived of most social contact in early childhood, our development appears irrevocably impaired. The etiology of only few feral children is documented in depth. Kaspar Hauser is one such case. In Werner Herzog's wonderfully detail-oriented movie "The Enigma of Kaspar Hauser," Bruno S. plays the role of Kaspar so astonishingly real that the movie strikes us as a documentary. This may come as no surprise. Herzog is a brilliant cinematic portrait artist, and Bruno Schleinstein seems predestined for this role, when we learn about his life. Michael Kimmelman published a passionate, yet distanced account on this man in The New York Times on Dec. 24.

Bruno S. possesses the great natural gift to act in one role, that is, as the feral child Kaspar Hauser. In Herzog's epic description of bucolic life in a small town in nineteenth century southern Germany, the story of Kaspar teaches us that we may not be able to attain the language skills necessary to grasp the intricacies of human relations when barred extensively from interacting with others in early childhood. As long as we find sufficient access to language, our mind will develop fine. Social relationships play a fundamental role in this process. The inability to express ourselves in language both constitutes and reflects a disability of thought, hindering the ordinary development of self-awareness. Hence, a meaningful Theory of Mind must consider abstract thought expressed in language and detached from senses as one bearing pillar of our psyche.

Two areas on the left cortical hemisphere are known to play fundamental roles in the processing of language. In an oversimplification, Wernicke's area appears instrumental in the comprehension of speech; Broca's area is crucial for speaking. Functional magnetic resonance imaging studies on the cerebral activation of Braille readers that my colleagues and I carried out (Melzer and others, 2001) suggest that, in addition, regions where visual, auditory, and somatic sensory association areas meet may be engaged in the phonetic and semantic processing of symbolic language. In his book "Language and Mind",Noam Chomsky proposes that language originates from innate roots. A vivid discussion of his ideas with Michel Foucault can be found here. Forkhead box P2 genes, FOXP2 genes for short, have been identified to substantially affect the development of language skills. Recent research provides evidence that these genes may have been expressed already in Neanderthals (Krause and others, 2007). Therefore, hereditary boundaries are set for the nerve cell mechanisms that underlie the development of language. These limitations need to be explored in depth and a valid Theory of Mind must take them into consideration.

Addenda

  • A second installment for a Theory of Mind has been posted (02/20/2009).
  • FOXP2 genes encode transcription factors. That is, their protein products control the expression of other genes, influencing cascades of developmental events. In a letter to this week's issue of the journal Nature, Konopka and others (2009) report that the product of chimpanzee FOXP2 differs only in two building blocks (amino acids) from that found in humans. Inserting the chimpanzee gene into the DNA of cultured human nerve cells resulted in distinct modifications of the proteins the cells synthesized. The observed differences may be relevant for the development of a speech apparatus (11/11/09).
  • In his new book with the title "Through the Language Glass: Why the World Looks Different in Other Languages", Guy Deutscher gives great examples for the fashion in which our language shapes our mind and vice versa? An excerpt of his book can be found in this weeks' New York Times Magazine entitled "Does Your Language Shape How You Think?". The author convincingly demonstrates in astounding examples that language distinctly reflects differences in the perception of space and geographic position in cultures that use an absolute system of reference, that cardinal points (East, West, North, South), as opposed to a relative system, that is body-centric reference (left, right, in front, behind). Lera Boroditsky provides more details in her essay for The Wall Street Journal with the title "Lost in Translation" published online  Jul. 23, 2010. Self-conscience seems to differ accordingly. In a culture using absolute reference, the individual is not surrounded by her/his environment, but situated in it (08/28/10).
  • Neanderthals were not that different from us. It is not unreasonable to assume that they were able to speak to each other. The Smithsonian Institution recently unveiled MEanderthal, a face morphing mobile application that may drive this point home (09/03/10)
  • You may wish to listen to this interview with Werner Herzog by Tom Ashbrook with the title "Filmmaker Werner Herzog", originally broadcast on National Public Radio's On Point Dec. 11, 2009 (09/06/10).
  • In this interview by Steve Inskeep on National Public Radio's Morning Edition with the title "From Werner Herzog, Three DVDs Worth A Close Look" aired today, Werner Herzog recommends three movies for us to watch (09/16/10):
  • This comprehensive review by Kuhl (2010) provides detailed insight into recent findings on early language and brain development, using the latest technology (10/10/2011)
References
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