EFFECTS OF EFFORT AND SOCIAL MODELING ON DRINKING IN HUMANS

The role of economic and social influences on water intake in humans w as explored in two experiments. In the first experiment, the effect of water cost (as defined as the amount of effort required to acquire wa ter) on prandial drinking was studied by manipulating water position d uring an ad libitum meal: water was available either on the dining tab le, about 20 feet from the table, or approximately 40 feet away. Subje cts drank significantly more when the water was on the table than in t he other conditions; but a linear relationship between cost (distance) and intake was not observed. In the second experiment, the effects of water cost and a social model on drinking were assessed in a similar paradigm. Increasing effort required to obtain water significantly red uced prandial water intake, and the presence of a social model increas ed water intake. Although some interesting trends emerged, no signific ant interactions between social and economic factors were found. These experiments demonstrate that environmental factors can significantly affect facultative drinking in humans. (C) 1996 Academic Press Limited