Collier G, Johnson D F, Borin G, Mathis C E
Department of Psychology, Rutgers University, New Brunswick, New Jersey 08903.
J Exp Anal Behav. 1994 Sep;62(2):169-84. doi: 10.1901/jeab.1994.62-169.
Rats in a laboratory foraging paradigm searched for sequential opportunities to drink in two water patches that differed in the bar-press price of each "sip" (20 licks) of water within a bout of drinking (Experiment 1) or the price and size (10, 20, or 40 licks) of each sip (Experiment 2). Total daily water intake was not affected by these variables. The rats responded faster at the patch where water was more costly. However, they accepted fewer opportunities to drink, and thus had fewer drinking bouts, and drinking bouts were smaller at the more costly patch than at the other patch. This resulted in the rats consuming a smaller proportion of their daily water from the more costly patch. The size of the differences in bout frequency and size between the patches appears to be based on the relative cost of water at the patches. The profitability of each patch was calculated in terms of the return (in milliliters) on either effort (bar presses) or time spent there. Although both measures were correlated with the relative total intake, bout size, and acceptance of opportunities at each patch, the time-based profitability was the better predictor of these intake measures. The rats did not minimize bar-press output; however, their choice between the patches and their bout sizes within patches varied in a way that reduced costs compared to what would have been expended drinking randomly. These data accord well with similar findings for choices among patches of food, suggesting that foraging for water and food occurs on the basis of comparable benefit-cost functions: In each case, the amount consumed is related to the time spent consuming.
在实验室觅食范式中，大鼠在两个饮水区域寻找连续的饮水机会，这两个区域中每一口（20次舔舐）水的按杆代价在一次饮水过程中有所不同（实验1），或者每一口水的代价和量（10、20或40次舔舐）有所不同（实验2）。每日总饮水量不受这些变量的影响。大鼠在水代价更高的区域反应更快。然而，它们接受的饮水机会更少，因此饮水次数更少，而且在代价更高的区域，每次饮水的量比在另一个区域更小。这导致大鼠从代价更高的区域摄入的每日水量比例更小。两个区域之间每次饮水次数和量的差异大小似乎基于区域内水的相对代价。每个区域的收益性是根据在该区域付出的努力（按杆次数）或花费的时间所获得的回报（毫升数）来计算的。虽然这两种衡量方式都与每个区域的相对总摄入量、每次饮水的量以及对饮水机会的接受程度相关，但基于时间的收益性是这些摄入量衡量指标的更好预测指标。大鼠并没有使按杆输出最小化；然而，它们在两个区域之间的选择以及在每个区域内每次饮水的量以一种相比于随机饮水所花费的成本有所降低的方式而变化。这些数据与在食物区域选择方面的类似发现非常吻合，表明对水和食物的觅食是基于可比的收益 - 成本函数进行的：在每种情况下，摄入量都与摄入所花费的时间相关。
