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.
【視聽(tīng)版科學(xué)小組榮譽(yù)出品】
session freely available sipped costlier a bitter taste
你老爸可能說(shuō)過(guò)：“你越努力為某樣?xùn)|西工作，你就越欣賞它?！焙芎?，你父親確實(shí)知道得很多。因?yàn)橐豁?xiàng)新的研究發(fā)現(xiàn)，老鼠越努力去得到某種食物，這種食物味道就越好。這項(xiàng)研究刊登在《皇家學(xué)會(huì)學(xué)報(bào)》上。 研究人員訓(xùn)練老鼠去推動(dòng)控制桿，推動(dòng)之后能得到兩種報(bào)酬中的一種——推動(dòng)第一個(gè)控制桿，就會(huì)滲出一滴糖水；推動(dòng)第二個(gè)控制桿，它們則能得到另一滴不同味道的糖水。 然后事情開(kāi)始變得有趣了?？茖W(xué)家逐漸加大獲得其中一種糖水的難度，從剛開(kāi)始的推動(dòng)一次控制桿，到后來(lái)的推動(dòng)五次、十次……再到最后要你推動(dòng)十五次。因此，在實(shí)驗(yàn)的最后時(shí)間里，獲得這種糖水消耗的精力是獲得另一種的十五倍。 隨后這些老鼠回到它們的籠子里，這時(shí)兩種糖水都是無(wú)償供應(yīng)的。老鼠們對(duì)那種更難獲得的糖水表現(xiàn)出強(qiáng)烈的偏愛(ài)。根據(jù)它們喝水的速度推斷，看來(lái)老鼠們覺(jué)得代價(jià)更高的糖水味道更好。 這結(jié)果有著一定的進(jìn)化意義。假如加倍努力只能換來(lái)滿嘴的苦澀，那這種動(dòng)物就不會(huì)努力讓自己存活下來(lái)了。