Maybe your dad said, “The harder you work for something, the more you’ll appreciate it.” Well, father really did know best. Because a new study finds that the harder mice have to work for a treat, the better it tastes. The research appears in the Proceedings of the Royal Society.
Mice were trained to push levers to get either of two rewards. Press one lever, out comes a drop of sugar water. Press the other and they get a drop of different tasting sugar water.
Then things got interesting. For one of the treats, scientists gradually increased the amount of effort required for the payoff—from one lever-press to five, then 10, then 15. So by the end of the ____1____ , one type of sugar water cost 15 times more effort than the other.
The mice then retired to their home cage where both treats were ____2____. And they showed a strong preference for whichever reward they’d worked harder to obtain. Based on how fast the mice ____3____, they appeared to find the ____4____ sugar water more tasty.
Which makes evolutionary sense. An animal wouldn’t survive if a little hard work left ____5____ in its mouth.
【视听版科学小组荣誉出品】
session freely available sipped costlier a bitter taste
你老爸可能说过：“你越努力为某样东西工作，你就越欣赏它。”很好，你父亲确实知道得很多。因为一项新的研究发现，老鼠越努力去得到某种食物，这种食物味道就越好。这项研究刊登在《皇家学会学报》上。 研究人员训练老鼠去推动控制杆，推动之后能得到两种报酬中的一种——推动第一个控制杆，就会渗出一滴糖水；推动第二个控制杆，它们则能得到另一滴不同味道的糖水。 然后事情开始变得有趣了。科学家逐渐加大获得其中一种糖水的难度，从刚开始的推动一次控制杆，到后来的推动五次、十次……再到最后要你推动十五次。因此，在实验的最后时间里，获得这种糖水消耗的精力是获得另一种的十五倍。 随后这些老鼠回到它们的笼子里，这时两种糖水都是无偿供应的。老鼠们对那种更难获得的糖水表现出强烈的偏爱。根据它们喝水的速度推断，看来老鼠们觉得代价更高的糖水味道更好。 这结果有着一定的进化意义。假如加倍努力只能换来满嘴的苦涩，那这种动物就不会努力让自己存活下来了。