According to Ryuta Kawashima - the designer of the popular "Brain Training" computer software, riding motorcycles help keep drivers young by invigorating their brains, "The driver's brain gets activated by riding motorcycles" in part because heightened alertness. "In a convenient and easy environment, the human mind and body get used to setting the hurdle low", he warned. "Our final conclusion is that riding motorcycles can lead to smart ageing."
I just wonder how does this differ from driving manual four wheel vehicles? One thing for sure, based on my observation that "If you are not carefull, motorcycles will keep you young because you won't grow old."