Measuring one's physical height may be innacurate if one's lying down. A large and significantly increasing amount of it has been attributed to genes, see the link below. FMRIs show an observable and genetic difference in the temporal and occipital lobes of intelligent people who tend to become more successful. The test correlate well with physical aspects. It doesn't make one a good person or guarantee accomplishments. It does mean the ability to do some things others cannot. https://www.technologyreview.com/s/610339/dna-tests-for-iq-are-coming-but-it-might-not-be-smart-to-take-one/