I think that book is rubbish here is an article about how athletes really need
talent.The fact that the best women can't run as fast as men shows that sporting success must be due to genes as not having the Y chromosome makes such a huge difference proving the book to be utter rubbish as it mentions sporting stars.
I have already quoted studies showing that genetics is the dominant factor, indeed it has to be or Darwin was wrong as humans have developed intelligence superior to animals and must have done by evolution if Darwin was right and thus intelligence must be highly genetic.
My own experience would prove you wrong as I excelled at school even when I didn't try hard I use to only work hard for exams and during my AS year I had major depression difficulties which meant I had to have regular GP visits and I really was losing the motivation to do my work and I didn't revise for my mocks but I got near to 100% in my Maths and Physics ones.Also, my college lecturers use to get really angry at how lazy some of my Maths friends were as they would barely do any work in the class and some students didn't like it as they always ended up getting great grades where as they worked and still couldn't understand it.Another part of my proof will be Stephen Hawking, if you do some research you will find he was a very lazy student and he didn't complete a lot of his exams as he couldn't remember stuff but just about got a first through stuff he could naturally do.
I think my school experiences are probably even better indicators as I didn't work until the exams for most of school and yet I achieved near to the best grades in mock exams and tests and generally performed the best in class quickly grasping concepts quicker than anyone else could from a very young age.Like I said earlier I think noone in the class could factorise quadratics but I could factorise them in my head just naturally.One of Maths teachers use to consider me naturally gifted in Maths and teachers generally saw me as an incredible genius and students sometimes complained when teachers said I had finished and why they hadn't because they couldn't be expected to compete with me and my teachers often speculated about how famous I would become(they did get carried away though).
However, I do know some clever students at school and teachers would even say this at times who could do a lot better but didn't perform too well as they didn't behave and weren't motivated to do well.
I'd certainly agree that you generally need training with natural talent(maybe not the case if you are an incredible genius like Hawking?), which is exactly why I support Grammar Schools to give the cleverest students from poor backgrounds their best chance and to prevent them misbehaving and losing motivation to do well.Working Class Students are much less likely to have the natural talent required so even training won't help them.Its clear without natural talent you have very little and you have some chance if you only have natural talent but to maximise your chances you need training and natural talent.
I am very lucky to be naturally gifted from an underclass background probably due to my parents carrying good genes, genes that have been successful in my Uncles/Aunt who were very successful my Uncle got the best results at school(like me) and got a PhD and did end up becoming a millionaire.