Food variance and temporal discounting in socially foraging chicks.
Food variance and temporal discounting in socially foraging chicks.
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社交觅食雏鸡的食物差异和时间折扣。
DOI：
10.1016/j.anbehav.2016.07.032
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发表时间：
2016
期刊：
影响因子：
2.5
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Mizuyama;R.;Uno;L.;Matsushima;T.
以往的研究表明，国内小鸡，Gallusgallus arteriticus，在竞争性觅食条件下训练，随后会发展出高度的冲动，在跨期选择范式。竞争不可避免地会导致觅食者获得的食物量的变化。然而，目前尚不清楚食物的差异是否与冲动有因果关系。在实验1中，我们比较了四组小鸡在两种社会条件（伪竞争或隔离）和两种食物条件（可变或恒定的食物）的组合训练。根据二项分布，通过改变每次试验中的谷物数量来引入食物方差。受试鸡与竞争鸡之间被一堵透明墙隔开，没有发生实际干扰。随后，在隔离和恒定的食物条件下，在短时间延迟后的小奖励（SS）和长时间延迟后的大奖励（LL）之间进行二元选择测试。在假竞争和可变食物条件下训练的雏鸡，选择LL的频率显著低于其他三组。当省略LL延迟时，这种效应消失，表明小鸡准确地记住了食物量。因此，食品方差是更强的时间折扣的必要条件。否则，观察到的效果可以归因于一个矛盾的风险倾向与变量选项。在实验二中，我们比较了四组雏鸡，其中的食物量变化的SS或LL，或两者兼而有之。随后的二元选择测试表明，小鸡选择SS，无论SS或LL是否有变化。这些结果不能解释为更大的风险倾向选择的可变选项。巧合的感知竞争和食物的差异，至少在一个选项，是足够的小鸡发展选择冲动。
Previous studies have shown that domestic chicks,Gallusgallus domesticus, trained in a competitive foraging condition would subsequently develop a high degree of impulsiveness in an intertemporal choice paradigm. Competition inevitably causes variance in the amount of food that the foragers gain. However, it is not known whether the food variance is causally linked with the impulsiveness. In experiment 1, we compared four groups of chicks trained in combinations of two social conditions (pseudocompetition or isolated) and two food conditions (variable or constant food). The food variance was introduced by varying the number of grains in each trial according to a binomial distribution. The subject chick was separated from the competitors by a transparent wall, and no actual interference occurred. Chicks were subsequently tested in binary choices between a small reward after a short delay (SS) and a large reward after a long delay (LL) in an isolated and constant food condition. If chicks had been trained under the pseudocompetition and variable food, they chose LL significantly less frequently than the other three groups. The effect disappeared when the LL delay was omitted, suggesting that chicks accurately memorized the food amount. The food variance is thus a necessary condition for the stronger temporal discounting. Otherwise, the observed effect could be ascribed to a paradoxical risk proneness associated with the variable option. In experiment 2, we compared four groups of chicks in which food amount varied either in SS or LL, or both. The subsequent binary choice tests revealed that the chicks chose SS irrespective of whether SS or LL had varied. These results cannot be explained in terms of a greater risk-prone choice of the variable option. Coincidence of perceived competition and food variance, at least in one option, is sufficient for chicks to develop choice impulsiveness.