together to form words. The same applied to our acquisition of read- 

 ing. Once we had developed the necessary expertise with these 

 things, however, we could walk, talk and read without having to 

 concentrate on the individual steps, syllables and letters. Our focus 

 of attention could then be directed toward the broader goals of 

 many-step journeys and main -word sentences. 



Ian Tattersall (1998) considered the evolution of the human ca- 

 pacin in his own James Arthur Lecture, and showed how this ex- 

 panded as the front of the brain became larger. That part of the brain 

 houses the prefrontal cortex, as was discussed earlier, and it seems 

 logical to conclude that the gradual augmentation of our faculties 

 was a result of an increased ability to manipulate schemata, and to 

 consolidate them into increasingly sophisticated versions. Support 

 for this view comes from the appalling injury sustained by Phineas 

 Gage in 1848 (Harlow. 1868). He inadvertently created a spark 

 while compressing a charge of gunpowder with an iron tamping rod. 

 and the ensuing explosion drove the rod through the front of his 

 head. The case is an important one in medical history because the 

 damage brought about a dramatic change in Gage's personality. 

 Originally polite, gifted and conscientious, his post-trauma state was 

 characterised by shiftlessness and frequent lapses into profanity. The 

 recent computer-aided reconstruction of an image of his brain, using 

 his surviving skull, by Hanna Damasio and her colleagues (1994). 

 demonstrated that Gage's prefrontal cortex had suffered massive 

 damage, whereas his motor-directing areas had been spared. This 

 conforms with the ideas I have been expressing, because such injury 

 would have severely curtailed his higher faculties, while not pre- 

 cluding consciousness. 



We have not yet considered the actual mechanism whereby novel 

 schemata are incorporated into the creature's behavioral repertoire. 

 As a preliminary, let us consider the central role played by the 

 muscle-directing region. It must orchestrate the movements of all 

 the skeletal muscles, making sure that conflict does not arise (Cot- 

 terill. 1995). Let us consider a simple example. A specific pattern 

 of muscular movements will raise my hand to my mouth and place 

 some of my fingers between my teeth. Then another set of muscular 

 movements will cause mv teeth to bite through my fingers and sever 



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