Isaksson Emil, Utku Urhan A, Brodin Anders
Department of Biology, Ecology Building, Lund University, S-223 62 Lund, Sweden.
Behav Ecol Sociobiol. 2018;72(7):118. doi: 10.1007/s00265-018-2529-z. Epub 2018 Jun 26.
Cognitively advanced animals are usually assumed to possess better self-control, or ability to decline immediate rewards in favour of delayed ones, than less cognitively advanced animals. It has been claimed that the best predictor of high such ability is absolute brain volume meaning that large-brained animals should perform better than small-brained ones. We tested self-control ability in the great tit, a small passerine. In the common test of this ability, the animal is presented with a transparent cylinder that contains a piece of food. If the animal tries to take the reward through the transparent wall of the cylinder, this is considered an impulsive act and it fails the test. If it moves to an opening and takes the reward this way, it passes the test. The average performance of our great tits was 80%, higher than most animals that have been tested and almost in level with the performance in corvids and apes. This is remarkable considering that the brain volume of a great tit is 3% of that of a raven and 0.1% of that of a chimpanzee.
The transparent cylinder test is the most common way to test the ability of self-control in animals. If an animal understands that it only can take food in the cylinder from the cylinder's opening and controls its impulsivity, it passes the test. A high level of self-control has been demonstrated only in cognitively advanced animals such as apes and corvids. Here, we demonstrate that the great tit, a small song bird that is very good at learning, performs almost in level with chimpanzees and ravens in this test.
通常认为，认知能力较高的动物比认知能力较低的动物具有更好的自我控制能力，即能够为了延迟奖励而拒绝即时奖励。有人声称，这种能力的最佳预测指标是绝对脑容量，这意味着大脑袋动物的表现应该优于小脑袋动物。我们对大山雀（一种小型雀形目鸟类）的自我控制能力进行了测试。在这种能力的常见测试中，给动物展示一个装有一块食物的透明圆柱体。如果动物试图透过圆柱体的透明壁获取奖励，这被视为冲动行为，测试失败。如果它移动到开口处并以此方式获取奖励，则测试通过。我们的大山雀的平均通过率为80%，高于大多数已测试的动物，几乎与鸦科鸟类和猿类的表现相当。考虑到大山雀的脑容量仅为渡鸦的3%，黑猩猩的0.1%，这一结果非常显著。
透明圆柱体测试是测试动物自我控制能力最常用的方法。如果动物明白它只能从圆柱体的开口处获取其中的食物并控制其冲动性，那么它就能通过测试。只有在认知能力较高的动物如猿类和鸦科鸟类中才证明具有高水平的自我控制能力。在此，我们证明了大山雀，一种非常善于学习的小型鸣禽，在这项测试中的表现几乎与黑猩猩和渡鸦相当。
