(CNN) -- Lewis Hamilton has always been driven by his emotions -- for better or for worse -- but has he found a new level of maturity with Mercedes? The double world champion has been schooled in the harsh lessons that Formula One can mete out since he joined McLaren's junior program when just 13 years old. But, despite this careful education by one of the most straight laced teams in F1, the British boy racer cannot help wearing his heart on his sleeve. There have been some heady highs and mesmerizing meltdowns in his eight-year career at the highest level of motorsport.
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Lewis Hamilton added a second world title to his 2008 crown with victory for Mercedes in 2014
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"Hamilton is more mature," says the British racer's biographer Mark Hughes
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Teammate and title rival Nico Rosberg has raised credibility with his 2014 performance
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Hamilton can match Juan Manuel Fangio's two world titles for Mercedes in 2015, says former racer John Watson
Formula One
F1
Hamilton's inner calm held out despite an @placeholder season filled with flashpoints that threatened to derail his peace of mind.
Lewis Hamilton
Lewis Hamilton
Hamilton
Hamilton
"@placeholder has evolved to be able to deal with the stress.
Lewis Hamilton
Lewis Hamilton
Hamilton
Hamilton
"That induces @placeholder to over-strive sometimes and that happened on three or four occasions in qualifying this year."
Lewis Hamilton
Lewis Hamilton
Hamilton
Hamilton
"Even when Nico out-qualifies him, we see @placeholder is faster in the race because the tires wear, the track temperature changes, the fuel load changes, the car is never perfection," Hughes adds.
Nico Rosberg
"Lewis' level has lent @placeholder a credibility that is greater than it would have been without Lewis."
Juan Manuel Fangio
@placeholder has done that and now so has Lewis Hamilton."
Lewis Hamilton
Lewis Hamilton
Hamilton
Hamilton
Fangio has done that and now so has @placeholder."