Thursday, March 07, 2013

Descartes' Dogs

It is well known in the history of psychology that Descartes was an early thinker on what we would now call classical conditioning or Pavlovian conditioning, which he referred to as “reflex”. Most authors writing on the subject cite two of his works and one letter to make the connection clear . . . However, another much earlier epistolary reference seems generally to be missed: his letter to his friend Marin Mersenne, dated 18 March 1630. What is particularly interesting in this earlier letter to Mersenne is Descartes association of sound (in this case the sound produced by a violin) to the ‘reflex’ response of dogs. As a precursor to Pavlov, and the Pavlovian dogs experiment, it is interesting to see Descartes constructing what is a remarkably parallel experimental test — albeit, in Descartes case and as far as we know, a thought experiment only. . . . It is striking just how similar Descartes’ theory on ‘reflex’ is to Pavlov’s theory of ‘conditioning’. Just as in Pavlov’s conditioning experiment, performed two hundred and seventy one years after Descartes’ letter outlines his theory of ‘reflex’, the two stimuli necessary for conditioning, the conditioned and unconditioned stimuli, are paired causing the ‘planned conditional response’. In Descartes’ letter, the planned conditional response is fear. In Pavlov’s experiments, the planned conditional response is the saliva elicited by hunger. more

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