Terry Eastland, the author who wrote From Ending Affirmative Action: The Case for Colorblind Justice states, "Most arguments for affirmative action fall into two categories: remedying past discrimination and promoting diversity". Eastland believes that the founders of affirmative action did not anticipate how the benefits of affirmative action would go to those who did not need it, mostly middle class minorities. Additionally, she argues that affirmative action carries with it a stigma that can create feelings of self-doubt and entitlement in minorities. Eastland believes that affirmative action is a great risk that only sometimes pays off, and that without it we would be able to compete more freely with one another. Libertarian economist Thomas Sowell identified what he says are negative results of affirmative action in his book, Affirmative Action Around the World: An Empirical Study. Sowell writes that affirmative action policies encourage non-preferred groups to designate themselves as members of preferred groups [i.e., primary beneficiaries of affirmative action] to take advantage of group preference policies; that they tend to benefit primarily the most fortunate among the preferred group (e.g., upper and middle class blacks), often to the detriment of the least fortunate among the non-preferred groups (e.g., poor white or Asian); that they reduce the incentives of both the preferred and non-preferred to perform at their best – the former because doing so is unnecessary and the latter because it can prove futile – thereby resulting in net losses for society as a whole; and that they engender animosity toward preferred groups as well.:115–147
What argument does Sowell make in his claim that non - preferred minorities have less incentive to perform at their best?
because it can prove futile