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JOURNAL ARTICLE Bird Song and theProblem of Honest Communication: How is the honesty of animal signalsmaintained when exaggeration and bluff are so tempting? William A. Searcy andStephen Nowicki American Scientist Vol. 96, No. 2(MARCH-APRIL 2008), pp. 114-121 Published by: Sigma Xi, The ScientificResearch Honor Society Stable URL:https://www.jstor.org/stable/27859118 Page Count: 8 Many animals communicateinformation about their fitness through vocalizations directed to potential matesand competitors alike. (In fact, people are no exception.) From an evolutionarystandpoint, however, what preserves the integrity of such messages? Would not exaggerationprovide a competitive advantage? What biologists call signal reliability is nowa central question in animal behavior, and bird song has been a model for studying it for morethan a half century. The authors are investigating signaling in male song sparrows (Melospiza meladia), which use the same songsfor both courtship and aggression. The Cost of Singing Softly Given that soft song isindeed the display that most reliably predicts attack in song sparrows, what is tokeep males from cheating in order to appear more aggressive? Again, to answer thisquestion one must take another look at the handicap hypothesis, in which the costsof signals are crucial to enforcing their honesty. Scientists have proposed different types of expenses that could beincurred for aggressive signals, butmost seem unlikely to apply to soft song. Energycosts, for one, are still unlikely because songs in general, and those oflow intensity in particular, take very little energy to produce. The kind of developmental cost discussedearlier for song repertoire size also seems unlikely,because these costs are more likely to apply to signals established over the longterm, rather than signals that change over the short term at will. A thirdpossibility is what is called a ”vulnerability cost,” where the manner in which a signal is producedinherently makes the individual giving it more vulnerable to attack. A vulnerability cost might seem plausible forsoft song if, becauseof its low amplitude, it can only be perceived by a receiver when the singer isclose by, making it an unambiguoussignal of proximity and thus vulnerability. However, because of the way thatsound attenuates with distance, a signal that issoft when it reachesthe receiver could beeither a low-intensity signal produced near the signaler or a high-intensity signalproduced farther away. By contrast, a signal that is loud when it reaches thereceiver is actually less ambiguous in conveying that the signaler is close by. repertoire (noun) = all the songs, pieces of music, etc. that a performerknows and can perform at will = If you can do something at will, you can do it anytime you want attenuate (verb) = to make something smaller, thinner, orweaker We have argued that soft song is a reliable aggressive signal because it is an unambiguous and costly signalof attention, not of proximityor vulnerability. Soft song is usually producedquite close to the intendedreceiver, so that the receivercan both see and hear the singer. The listener then should be able to discern thevolume at which the song is produced, and because of its low volume, soft song isunlikely to be audible to any other individuals. Thus by singing at low intensitynear a rival, the singer is indicating that its attention is focused solely on thatparticular bird. Soft songs are alsocostly to the singer because they are unlikely to reach other targets. In the caseof female receivers,the cost could be a diminished proclivity to mate,as we have shown that femalesong sparrows find softsong less attractive than songs sung at a normal broadcast amplitude. The more-significant costof soft song, however, is probably that other male receivers fail to hear a responsefrom the male being challenged, leading neighbors or other potential usurpers to be more likely to intrude on the soft-singer’sterritory. proclivity (noun) = a natural tendency to do something or tofeel something, often something bad usurp (verb) = to take somebody’s position and/or powerwithout having the right to do this A recent study of ours supportsthe idea that soft songis costly because it limits reception to a single intended receiver. In this experiment,we simulated singing interactions between an intruder and a territory owner, inwhich the latter sang softly or at a normal level. First we recorded the territoryowner and mapped his territory; then we captured and held him temporarily. Whilethe owner was held, we placed two loudspeakers on his territory, and staged a virtualinteraction by playing an intruder's song through one speaker and the owner’s songfrom the other. The intruder song was recorded from a male holding a distant territory,and was always played at normal level. In half the trials, the owner’s song wasalso played at normal level, and in the other half the owner’s song was played ata level typical of soft song. The result was that intrusions by other male song sparrows were more common and moreserious when the simulated owner sang soft songs than when he used loud song. Presumably,other males listening to the interaction from off the territory cannot hear theowner when he uses soft song, and thus cannot tell that he is countering the intruder.Thus by using soft song to signal his focused attention to one intruder, the territoryowner sacrifices his ability to ward off other potential intruders. 一共两段，大半瓶，第一段是说雄性的某种鸟会soft sing，然后说这种sing 有的是有效的，有的是无效的（考试的时候没看清逻辑，说的可能有点奇怪/捂脸）。 第二段好像是在找这种softsing 的解释，首先提出了一个energycost（这个词记得很清楚），后来好像否定了这个观点。 然后又提出了一个attack cost（好像是叫这个），说这种sing能帮助雄鸟吸引还是躲避天敌来着（忘了）。最后作者的态度，emmmm，狗主实在没时间去琢磨了，抱歉。 鸟用soft的叫声警示敌人 有一种鸟用soft的叫声来警示敌人？为什么是soft的叫声呢，因为这种警示的行为是有cost的。 V1: (By nabalaxuan) 第一段：一种动物（好像是麻雀) 发出很轻的声音 如何从Natural selection的角度解释，有一个科学家说这涉及到一种cost
第二段：energy cost, 但这个解释不好，因为很轻，不用多少能量
vulnerable cost 这个是指动物发出声音是会把其暴露在predator面前的，所以轻易不会发出这个声音
V2: (By Espange, V23) 考到一个 说什么biologistcost来解释为什么公麻雀在表示要袭击敌人的时候温柔地叫。。。（soft singing ）
第一段说提出这个现象 有一个理论
第二段说另外几种解释。。。后来说会被敌人觉得ambiguity就是混淆了 就是麻雀本来是想吓唬敌人表示要袭击了 但是叫得太轻柔了 会被让敌人很迷糊 V3: (By Gem99333) 有一篇讲说公麻雀啊你温柔的叫。 说公麻雀温柔的叫的时候，其实是在预警，马上就要进攻敌人了！然后大家都觉得这个行为过于丧心病狂啊，怎么来解释这种行为呢？然后有一位大师挺身而出表示：这个问题嘛，可以用Biology SignalCost来解释。然后解释了一下这个Cost，但是说实话这句话我看的比较糊涂，但是大致是说如果 第二段呢就开始说，用Biology Cost解释似乎还是有那么一点问题的哎。然后它就分析了一下这个Cost可能是个啥。一方面呢，他可能是个ACost(专有名词失忆了，这一片都没有出题点所以看两眼过吧)，这个Cost是讲说，这样叫的时候消耗的能量比较小。但是这种说法不太成立，因为似乎本来消耗的能量就是非常小的。然后看另一方面，他有可能是个B Cost(重点)。《警示：后面的内容很！混！乱！因此不确保回忆准确，大家遇到这篇的话一定要用心读后面的内容，因为有出！题！点！》接着说这个B Cost，狗主理解这个成本说的是释放出“哥们儿我在这儿呢你特么给我小心点”这样的信号，就是说这个信号是要告诉对方自己已经接近了。但是作者认为这个解释也并不合理，因为这样的声音信号经过对手加工后会变得很混沌，就是对方根本无法通过这样的叫声判断出来这只破鸟到底在哪里。同时作者认为，与这样的温柔的叫相比，尖利的叫声更容易让对方确认自己就在附近，因此B Cost的解释也不合理。本文到此戛然而止，让感觉人不知所云。。。 有一个主旨题，失忆一道。另有一道通篇细节题，但重点考察B Cost之后。这里面请大家尤其注意：有一个选项说，作者认为他们温柔的叫声是否是为了把对手吓跑。考场上遇到这道题请务必认真分析，狗主认为不是，但犹豫了一会儿。 V4: (By Bobeyscript) 【P1】 说这种鸟的softsinging is a highly reliable signal of the intention to attack. 生物界里面有很多时候动物都会发出声音来signal potential attack (好像是这样，不太记得了~)但是不是所有signal都是reliable 的。 科学家提出一种假设，就说动物的这种行为存在biological cost——而这种cost使得unreliable的signal 逐渐消失（因为要耗cost,很浪费~），而最终剩下的都只会是reliable 的signal.
【P2】说这种biologicalcost存在的形式有很多种，其中一种不太可能的是“energy cost”(具体名词不记得了，可能是这个吧)。因为softsinging本身就不用耗能太多。比较可能的是“vulnerability cost”.然后就解释说为什么是v cost.
【P3】但是呢，即使有biologicalcost的存在，降低了unreliable的可能性，还是有不准确的地方。然后就举例说明。就说soft singing可能是一只鸟近距离发出的很soft的signal， 也可能是另一只鸟在远处发出很大声的signal.所以没有办法确切地知道发出声音的鸟的具体位置。
V5 (By Spagette, 780) 原文一共两段，第一段讲sparrow的叫声，尤其是那种轻柔的叫声到底是reliable还是unreliable的让研究人员比较困惑。第二段讲研究叫声靠不靠谱时涉及的两种biological costs，一种是energycost，一种是vulnerability cost。考了一个主题题，不记得答案了。考了一个细节题，答案是鸟的叫声大小不总是正确的反应鸟和receiver的距离，答案很确定。 V6 (By 匿名， V38)跟机经有点出入的是：作者对两钟cost的态度都是否定的，就是说这两个都不能解释为什么soft song是reliable的, 之前发的原文上很详细了。因为第二段有个地方说：the vulnerability cost will explan the reliability ifsoft song的接受者(receiver)认为....，但是这个if...不一定成立，因为远处的broad song也会让receiver认为在近处。
有个题问：以下哪种最可能，我选了麻雀soft song之后就开始打架...（因为第一段说soft song是reliable的）其他的选项都不对...
V7 (By alathen) Q1主旨题，
Q2，下面哪个是正确的，
A鸟叫得轻柔是为了节省生物能什么的
B鸟的叫得轻柔但是其实这货想表示aggressive action什么的 V8 (By 819474084,V40) 1. 下面哪个是文章中提到的那个研究的目的
选了：为了研究vulnerabilitycost对于reliable signal 的意义（meaning）
2.个细节题
答案是鸟的叫声大小不总是正确的反应鸟和receiver的距离
3.科学家研究energy cost是为了什么
我选了为了研究energy cost对reliablesignal 的影响（好像是这个意思）
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发表于 2018-7-9 22:01:45
