@Moderation 提到的那篇文献，我正好最近看过，在此与大家分享一下。
Bidirectional Control of Social Hierarchy by Synaptic Efficacy in Medial Prefrontal Cortex，这篇研究由当时还在中科院上海神科所的胡海岚课题组于2011年发表于Science上。文章采用小鼠作为研究对象，其中动物行为实验部分尤其出彩（不是说其他部分不出彩，但是行为部分的确是令人眼前一亮），能够在很大程度上解答题主的疑问。
作者开篇就点出目前社会等级的内在神经机制尚不清楚，而如果要研究社会等级的神经机制，首先你必须保证社会等级行为模型是具备足够的信度（稳定性）和效度（有效性），否则下一步的研究根本无从谈起（你如果能你自己研究的是不是社会等级都无法保证，如果进行更深层次的挖掘？这也是动物行为模型的重要性）。
作者在这里提供了一个验证社会等级的模型：Tube test,这里或许应该翻译为管道测验？具体如下：
研究者将四只C57/BL雄性小鼠（是黑色的，不是上图的那种）同笼饲养，出于社会性动物的本能，这四只雄性小鼠会自动分出个三六九等，此为背景介绍。
研究者将同笼饲养的两只小鼠从透明管道的两端放入管道内，当两只动物在管中相遇时，社会等级高的小鼠会步步紧逼，而社会等级低的小鼠则会不断后退，直到被迫退出管道。可以说，这是一个非常简单的行为实验，逻辑也非常清楚——高等级的小鼠前进，低等级的后退。只要对4只动物进行不断地两两配对，就可以清楚地判断这些动物的社会等级。
如果仅仅是这种水平的实验设计，当然不能发到Science上，出彩的是研究者提出的对该模型进行验证的三个判断标准(criteria)，分别是：(1) Transitivity;(2) Stability over time; (3) Consistency with results of other dominance measures，我在此粗略地称之为（1）等级的可传递性；（2）稳定性；（3）与其他社会等级测试的一致性。
首先，等级的可传递性，见下图：
第二，稳定性，如下图：
最后，与其他社交测试结果的一致性。
研究者一共采用了多达5种测试，碾灭了我对该模型的最后一丝怀疑。
①Visible burrow system(VBS):
The VBS apparatus and experimental protocol were adaptedfrom Arakawa et al. (3). In brief, the burrow system was comprised of an open fieldarea (61 cm ×61 cm) connected to a series of transparent tunnels and three opaquechambers. Food and water were available in the open field area, which was illuminatedon a 12:12 hr light/dark cycle. Specifically, our VBS included narrow ramps that lead tofood and water, accessible to only one animal at a time. In this experiment, cages offour male mice were housed in a VBS for 7 days. Weight change of each animal wascalculated as the weight before subtracted from weight after VBS.
简单来说，就是当对食物和水进行限制时，社会等级和体重改变呈线性关系。这很好理解，大哥先吃，小弟后吃，大哥吃饱了喝足了才轮到小弟，越晚吃的越少（也可能是竞争食物时处于弱势），等级越低的体重变化越大。最后结果和tube test的结果呈显著相关。
②Agonistic behavior test:
Mice housed together for a while do not exhibit extensiveaggressive behavior towards each other. However right after switched to a new cage,especially a dirty cage previously inhabited by other mice, they tend to engage a lotmore in agonistic activities presumably due to the need of claiming territory in the newenvironment. Taking advantage of this fact, we videotaped the mice with stable tube testrank right after the cage switch for 20 min. The number of offensive behaviors (lateralattacks, boxing, mounting and chasing) subtracting the number of defensive behaviors(flight, freezing and underside exposure during fight) was used to calculate thedominance score for each mouse. 16 out of 23 cages tested showed obvious dominant subordinate agonistic pattern.
短暂地把耗子放一起不会表现出过多的攻击行为，然而当放进新笼子，尤其是放进别的耗子用过的脏笼子的时候，为了争地盘，耗子会表现出更多的攻击性行为，录下来再评分，发现和tube test也是线性相关的（下同）。
③Barber test:
From more than 80 cages of male C57/BL6 mice, we found 7 cages, inwhich there was one mouse with intact whisker (barber) and the rest 3 mice withwhiskers trimmed or plucked (recipient). These mice usually aged > 14 weeks. In 3 ofthese 7 cages, there were additional hair losses on other body parts in recipient mice.
Tube test中主导地位的耗子喜欢拔别的耗子的毛和胡须。
④Urine-marking test:
For a cage of four male mice, six possible pairs of urine markingpatterns were tested (2 pairs/day, total 3 days) using the round robin design. Each pairof mice was placed in opposite sides of a wire mesh partition in a two-chamber cage (26cm × 21 cm × 26 cm)(4). Sheets of filter paper were spread below each cage to collecturine deposited by the animals. Mice were maintained in the urine-marking cages for 2hrs and then returned to their home cages. Urine marks on the filter paper werevisualized using the UV light source. The number and size of the marks and theirdistance from the partition were scored blindly to the tube test result. 8 cages of animalswere tested, yielding 48 pairs of results, among which 42 revealed obvious dominantsubordinate urine pattern.
Tube test中主导地位的耗子在新地盘尿的区域更大···
⑤Ultrasonic vocalization assay：
Mice were individually tested for ultrasonicvocalization in one side of a partition in a two-chamber cage (5). After habituation for10 minutes, a female was introduced in the opposite side and ultrasounds produced bythe mice were monitored (UltraVox, Noldus) for 5 minutes. The Mini-3 ultrasounddetector was set at 60 kHz, with the audio filter at level 7. The chamber was cleanedwith 0.5% bleach between two tests. In rare occasions when the female mouse urinated,test would be re-done.
面对母耗子时主导地位的耗子的求偶次数和频率要高于从属地位的耗子。
由于题主问的是如何用实验方法确定社会等级，我想上述回答在一定程度上已经足以解答题主的提问，我就不详细介绍本研究中后面的神经机制部分的结果了，一句话概括：内侧前额叶V层的椎体神经元的突触效能大小影响了小鼠社会等级的高低。
或许小鼠作为一种社会性动物并不如我们熟知的牛羊马那么典型，但在本研究中提出的社会等级评价的三个标准，在对任何动物的社会等级进行探索时都是适用的。只要符合可传递性、稳定性、并能被其他well-established方式验证的实验方法，无论研究什么社会群体，都是可信的、有效的。
回答完毕。
----------------
本人不是该研究方向的，对社会等级的相关文献阅读不多，若有谬误，还请指正！
此外，据说胡老师课题组最近用光遗传学把社会等级的研究推进了一步，不知道发表没有？如果有的话，希望能给个链接，谢谢！
耗子领袖 4小时前 0条评论- 上一个：备注托福，待准备哪些资料？
- 下一个：多次分书上的说明发生什么样可得的处?
