By Jim Davies

Runners can tell you that sometimes the last mile of a run seems to feel dramatically2. dramatically： 戲劇性地，格外地。longer than the first.This perceptual distortion isn’t limited to brains addled by exercise—it’s a consistent feature of our minds.3.這種感知失真不僅僅限于運(yùn)動引起的大腦混亂，而是一種我們的思維常態(tài)。perceptual： 知覺的，感知的；distortion： 扭曲，失真；addle： 變質(zhì)，變混亂；consistent： 始終如一的，一致的。

When we look at the world, it certainly feels like we’re seeing things as they really are, our senses measuring reality in an objective way. But numerous experiments have shown that the way we see the world is in fluenced by what we can do with it.

This way of thinking was pioneered by psychologist James Gibson, who came up with the idea of “affordances”:4. pioneer： v. 開辟，倡導(dǎo)；psychologist： 心理學(xué)家；affordance： 功能可見性，指事物所具有的功能可通過自身的外在形式表現(xiàn)出來，對于使用者來說，事物的功能是“可見的”。A ball affords picking up, and a hallway affords walking along it. When we look at a button, we perceive the affordance of pressing it. These are not optical illusions5. optical illusion： 視錯覺，指當(dāng)人觀察物體時，基于經(jīng)驗(yàn)主義或不當(dāng)?shù)膮⒄招纬傻腻e誤的判斷和感知。, as such, but changes in how we see the world according to what we want and can do. Here are some fascinating6. fascinating： 有趣的，極好的。examples.

你有沒有想過，為何沖刺前的最后一英里總是顯得特別長？為何你越想節(jié)食越抵抗不住美食的誘惑？為何在山頂比在山腳覺得山更陡峭？這個世界真的是“眼見為實(shí)”嗎？一起來看看我們的大腦是如何迷惑我們的吧！

The perceived height of a balcony is increased if you are afraid of falling. Hills look steeper if you’re elderly, tired, or wearing a heavy backpack; they look less steep after you consume a highcalorie drink.7. steep： 陡峭的；backpack：背包；consume： 消耗，消費(fèi)；high-calorie： 高熱量的。Because descending8. descend： 下去，沿……向下。a hill is more dangerous than going up it, hills look steeper from the top than from the bottom.That’s also why kids on the ground might think a tree is not too high, but after they climb it, they’re not so sure.

Hungry men prefer the looks of women with more weight on them, while men who are full prefer thinner women. We can speculate on9. speculate on： 推測，考慮。the reasons for this. It might be that hunger is associated with lean10. lean： 貧乏的，這里指“時間很少的”。eating times, and during those times,someone with enough resources to put on weight might be at an advantage to someone who’s thinner. This is supported by the finding that in poor areas, cultural ideals of feminine beauty are heavier than those in more af fluent cultures,11. feminine： 女性的；af fluent：富裕的。where the ideal woman is relatively thinner.

Food and drinks also look different according to our internal states.Thirsty people see bottles of water as being closer than people who aren’t thirsty.Your need for water makes the bottle look closer to encourage you to reach for it.

In general, we see desirable objects as closer.Dieters see muf fins12. muf fin： 松餅，小松糕。as being bigger than nondieters do. This raises an interesting question:

If people want to diet, then shouldn’t the food look smaller,and less appealing? The answer could be that the changes in perception work according to our subconscious drives, and less by our explicit goals.13When you are dieting, you are often at war with yourself. Part of you wants the muf fin, and part of you doesn’t. Looks like the part that wants the muf fin has more control over your perception.

Threatening things, such as spiders, are also perceived to be closer, and also larger and faster. At first glance, these two findings may seem mysterious, even contradictory14: Why would frightening things and desirable things look closer?Certainly your mind isn’t encouraging you to reach out and touch the spider like it is in the muf fin case. A desirable thing appearing closer encourages you to try to get it. A frightening thing appearing closer makes an already dangerous situation appear more urgent, encouraging you to get away. Hope and fear are compelling15. It’s the middle ground that’s boring. So even though both good and bad things look closer, it makes sense because closeness encourages different behaviors in these cases.

Physiological states, such as low blood glucose,16and social states, such as what kinds of friends are nearby,affect our perceptions of the world. We have evolved17to manage the resources we have, and our perceptual system helps us do that by changing our perceptions depending on the available resources. At the end of a run, your energy stores are depleted18, and your mind makes the last mile look longer to discourage you from wasting any more energy.

But it’s an illusion. A mile is a mile,no matter how tired you are.