Abstract
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.
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Selected References
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- Bauman R. An experimental analysis of the cost of food in a closed economy. J Exp Anal Behav. 1991 Jul;56(1):33–50. doi: 10.1901/jeab.1991.56-33. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Charnov E. L. Optimal foraging, the marginal value theorem. Theor Popul Biol. 1976 Apr;9(2):129–136. doi: 10.1016/0040-5809(76)90040-x. [DOI] [PubMed] [Google Scholar]
- Collier G. H., Johnson D. F., Hill W. L., Kaufman L. W. The economics of the law of effect. J Exp Anal Behav. 1986 Sep;46(2):113–136. doi: 10.1901/jeab.1986.46-113. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Collier G., Johnson D. F. The time window of feeding. Physiol Behav. 1990 Dec;48(6):771–777. doi: 10.1016/0031-9384(90)90225-s. [DOI] [PubMed] [Google Scholar]
- Herrnstein R. J. On the law of effect. J Exp Anal Behav. 1970 Mar;13(2):243–266. doi: 10.1901/jeab.1970.13-243. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson D. F., Collier G. H. Caloric regulation and patterns of food choice in a patchy environment: the value and cost of alternative foods. Physiol Behav. 1987;39(3):351–359. doi: 10.1016/0031-9384(87)90234-4. [DOI] [PubMed] [Google Scholar]
- Johnson D. F., Collier G. The relationship between feeding rate and patch choice. J Exp Anal Behav. 1991 Jan;55(1):79–95. doi: 10.1901/jeab.1991.55-79. [DOI] [PMC free article] [PubMed] [Google Scholar]