"Intelligence is largely inherited", claims a new twin study that used a high definition brain imaging technique to examine the quality of myelin in the brains of participants. UCLA neurology professor Paul Thompson and his colleagues used a faster version of a type of scanner called a HARDI (high-angular resolution diffusion imaging) that takes scans of the brain at a much higher resolution than a standard MRI to examine the quality of participants' myelin in several areas of the brain associated with intelligence.