IQ is largely fixed, but intelligence depends on context and approach.
Give a person an IQ test in elementary school and again when he or she is a senior citizen and science suggests the score will remain largely unchanged. Which means, like it or not, our sheer mental horsepower is largely fixed.
Source: 5 Mental Habits That Will Make You Much Smarter, According to an MIT Neuroscientist
My Comments: Pretty interesting stuff…