I think fubar may be right in a certain way: if you observe someone reaching a very high score while having a known poor environment (let's say you've tested them enough so one can ignore issues of <1 reliability causing a regression to the mean on subsequent retests), then you might then estimate that the non-environmental contributions must be unusually high - because something must be causing him to score very high, and it's sure not the environment. So for example, we might infer that his genes or prenatal environment or personality are better than average.