anchor: He knew that students would not find microeconomics, with its emphasis on efficiency, interesting unless they were first convinced that the economy could achieve more or less full employment, that it need not relapse into depression.
positive: He knew the only way he could make his students interested in microeconomics was to convince them that such principles of efficiency could promote employment and prevent relapse of the economy into depression.
negative: He knew the students would not care about microeconomics no matter how he presented the material.