tures possessing the capacity for consciousness. In the latter, sche- 

 mata can also be invoked consciously, and incorporated into the 

 creature's currently unfolding pattern of behavior. This ability re- 

 quires considerable sophistication in the underlying neural circuitry. 

 There have to be the internal feedback loops that mimic their ex- 

 ternal counterparts, the internal loops being able to invoke schemata 

 off-line and compare them with what is transpiring externally. As 

 discussed earlier, these loops emanate from the motor-directing re- 

 gion and are the conduits for efference-copy signals. The compari- 

 son function additionally requires an attention mechanism as well 

 as a means of evaluation. When the creature merely thinks, in the 

 absence of overt action, signals reverberate around the closed loops, 

 and the existence of working memory permits comparison of — and 

 choice between — competing schemata. In both the on-line and off- 

 line situations, working memory also permits consolidation of ex- 

 isting schemata into novel composite schemata (Cotterill, 1994). 

 And because evaluation must always be an integral part of this pro- 

 cess, one could say that this is the origin of our capacity for rea- 

 soning. 



Chris Frith (1992) has suggested that the alien voices heard by 

 victims of schizophrenia are really the inner voices of their own 

 imaginations, the erroneous perception stemming from a failure of 

 the efference-copy mechanism. It seems likely that such failure is 

 the result of malfunction at the biochemical level, rather than of 

 anatomical pathology, because the condition appears to be amelio- 

 rated by appropriate medication. Moreover, the schizophrenic person 

 nevertheless retains the capacity for consciousness, so the fault must 

 be rather selective. Something superficially resembling an efference- 

 copy mechanism was invoked by Germund Hesslow (1994), when 

 he considered the nature of thought, even though he did not use that 

 now-standard term. But he considered the internal loop as having 

 arisen as a sort of embellishment of the reflex route, embodied in 

 the stimulus-response paradigm that I criticised at the start of the 

 present essay. Hesslow acknowledged the writings of Alexander 

 Bain (1868) as one of the inspirations for his ideas, though Bain 

 was a forerunner of the now-defunct behaviorist school. I feel that 

 Hesslow put the cart before the horse, and that his view misses the 



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