Investigators tracked vital statistics of a colony of feral (wild) cats, searching for correlations between physical characteristics of the females, such as length and weight, and the number of kittens those females gave birth to. On average, the shorter, slightly heavier females tended to have more kittens. Investigators concluded that if this trend continues, in two hundred years the average female cat in the colony would be approximately 2 millimeters shorter and 70 grams heavier.

Editor: Articles in Gardening Magazine often spur sales of the plants they describe, particularly among people new to gardening. Accordingly, we will no longer publish articles or accept advertisements praising the beauty of trilliums and other rare wildflowers. Most such plants sold to gardeners are difficult to propagate under cultivation, so plant sellers often collect them in the wild. We are adopting this policy to help reduce the plundering of native plant populations.

Before the widespread acceptance of the efficiency-wage theory, scholars believed that increased worker productivity benefited workers in two ways: higher real wages and/or reduced working hours. According to the efficiency-wage theory, however, the causation can go the other way as well: productivity depends on the real wage paid by the firm. Productivity gains from higher wages result primarily from greater incentives to work coupled with diminished incentives to shirk, and secondarily from employers' ability to raise productivity by using higher wages to reduce turnover, improve morale, and attract superior applicants. Just as an efficiently higher wage may lower per-unit labor costs, so might judiciously shortened workweeks. Most workweek reductions, such as France's 1998 decision to implement a 35-hour workweek, are meant to ameliorate unemployment. While this is a worthy objective, the efficiency-week theory predicts far greater benefits. The theory asserts that an optimal number of hours worked per week will increase the productivity of the labor force for reasons akin to those argued by the efficiency-wage theorists. Moreover, an efficient week can have substantial social and economic benefits: workers will have more time to spend with family, as well as more time to consume a greater volume of goods.

Before the widespread acceptance of the efficiency-wage theory, scholars believed that increased worker productivity benefited workers in two ways: higher real wages and/or reduced working hours. According to the efficiency-wage theory, however, the causation can go the other way as well: productivity depends on the real wage paid by the firm. Productivity gains from higher wages result primarily from greater incentives to work coupled with diminished incentives to shirk, and secondarily from employers' ability to raise productivity by using higher wages to reduce turnover, improve morale, and attract superior applicants. Just as an efficiently higher wage may lower per-unit labor costs, so might judiciously shortened workweeks. Most workweek reductions, such as France's 1998 decision to implement a 35-hour workweek, are meant to ameliorate unemployment. While this is a worthy objective, the efficiency-week theory predicts far greater benefits. The theory asserts that an optimal number of hours worked per week will increase the productivity of the labor force for reasons akin to those argued by the efficiency-wage theorists. Moreover, an efficient week can have substantial social and economic benefits: workers will have more time to spend with family, as well as more time to consume a greater volume of goods.