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Consumer demand tests for animals are studies which determine the strength of motivation animals have for resources based on human patterns of purchasing resources with a limited income.〔Lea, S.E.G., (1978). The psychology and economics of demand. Psychological Bulletin, 85:441–466〕〔Dawkins, M.S., (1983). Battery hens name their price: consumer demand theory and the measurement of ethological "needs". Animal Behaviour, 31: 1195–1205〕 For humans, income and the cost of resources is usually measured in money; in animal studies the cost is usually a decrease in fitness represented by energy costs, time costs or a risk of injury.〔Dawkins, M.S., (1990). From an animal's point of view: motivation, fitness, and animal welfare. Behavioral and Brain Sciences, 13: 1–61〕 Costs of resources can be imposed on animals by an operant task (e.g. lever-pressing), a natural aversion (e.g. crossing water), or a homeostatic challenge (e.g. increased body temperature). For humans, as the cost of a resource increases, we usually decrease the amount purchased (or consumed), depending on how important we perceive that resource to be. Similarly, if we increase the cost of resources for animals (e.g. increasing the number of lever presses needed), then animals will reduce their consumption (i.e. gaining access) depending on how important they perceive the resource to be.〔Duncan, I.J.H., (1992). Measuring preferences and the strength of preferences. Poultry Science, 71: 658–663〕〔Sherwin, C.M., (1996). Laboratory mice persist in gaining access to resources: a method of assessing the importance of environmental features. Applied Animal Behaviour Science, 48: 203–214〕 Consumer demand tests therefore allow us to objectively quantify the strength of motivation animals have for resources whilst avoiding anthropomorphism and anthropocentrism.〔(【引用サイトリンク】title=Sherwin, C.M. Validating refinements to laboratory housing:asking the animals )〕 Using consumer demand tests one can empirically determine the strength of motivation animals have for a definite need (e.g. food, water) and also for resources we humans might perceive as a luxury or unnecessary but animals might not (e.g. sand for dustbathing〔Faure, J.M. and Lagadic, H., (1994). Elasticity of demand for food and sand in laying hens subjected to variable wind speed. Applied Animal Behaviour Science, 42: 49–59〕 or additional space for caged mice〔Sherwin, C.M. and Nicol, C.J., (1997). Behavioural demand functions of caged laboratory mice for additional space. Animal Behaviour, 53: 67–74〕). By comparing the strength of motivation for the resource with that for a definite need, we can measure the importance of a resource as perceived by the animals. Animals will be most highly motivated to interact with resources they absolutely need, highly motivated for resources that they perceive as most improving their welfare, and less motivated for resources they perceive as less important. Furthermore, Argument by analogy indicates that as with humans, it is more likely that animals will experience negative affective states (e.g. frustration, anxiety) if they are not provided with the resources for which they show high motivation.〔Dawkins, M.S., (1990). From an animal's point of view: motivation, fitness, and animal welfare. Behavioral and Brain Sciences, 13: 1–61〕 Various other aspects of the animal's behaviour can be measured to aid understanding of motivation for resources, e.g. latency (delay) to approach the point of access, speed of incurring the cost, time with each resource, or the range of activities with each of the resources. These measures can be recorded either by the experimenter or by motion detecting software. Prior to testing, the animals are usually given the opportunity to explore the apparatus and variants to habituate and reduce the effects of novelty. ==Terminology== The rate (i.e. regression line) at which the animal decreases its acquisition or consumption of a resource as the cost increases is known as the elasticity of demand. A steep slope of decreasing access indicates a relatively low motivation for a resource, sometimes called 'high elasticity'; a shallow slope indicates relatively high motivation for a resource, sometimes called 'low elasticity', or 'inelastic demand.' The 'break point' is the cost at which inelastic demand becomes elastic, i.e. the cost at which constant consumption begins to decrease. In human economics and consumer theory, a Giffen good is a resource which is paradoxically consumed more as the cost rises, violating the law of demand. In normal situations, as the price of a resource increases, the substitution effect causes consumers to purchase less of it and more of substitute goods. In the Giffen good situation, the income effect dominates, leading people to buy more of the good, even as its price rises. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Consumer demand tests (animals)」の詳細全文を読む スポンサード リンク
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