Pro-social behavior in rats is modulated by social experience.
Pro-social behavior in rats is modulated by social experience.
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作者：
Ben-Ami Bartal I;Rodgers DA;Bernardez Sarria MS;Decety J;Mason P
在哺乳动物中，帮助优先提供给自己群体的成员。然而，目前尚不清楚社会经验如何塑造亲社会动机。我们发现，老鼠帮助困住了陌生人，就像它们帮助笼子里的人一样。然而，老鼠不会帮助不同品系的陌生人，除非以前和被困的老鼠住在一起。此外，与不同品系的一只老鼠配对居住促使老鼠帮助该品系的陌生人，这证明老鼠将亲社会动机从一个个体扩大到其他表型相似的个体。为了测试基因相关性是否可以单独激发帮助，老鼠从出生起就与另一种菌株一起饲养，并没有暴露在自己的菌株中。成年后，寄养的老鼠会帮助寄养品系的陌生人，但不会帮助自己品系的老鼠。因此，表达亲社会行为需要紧张熟悉，甚至是对自己的紧张。DOI：http://dx.doi.org/10.7554/eLife.01385.001人类在可能不会帮助陌生人的情况下帮助家人和朋友。然而，他们也会通过直接行动来帮助完全陌生的人，比如帮助跌倒的人，也可以通过间接行动来帮助陌生人，比如向慈善机构捐款。本-阿米·巴塔尔等人。现在通过测试老鼠是否会帮助陌生人，如果是的话，在什么情况下帮助，来探索这种社会选择性帮助的生物学基础。在实验中，一只自由的大鼠暴露在另一只被困在塑料管中的大鼠身上，其中一只大鼠的门是向外的，为期12个小时。当用困在管子里的笼子测试时，大多数自由的老鼠在几天内学会了通过打开门来释放被困的老鼠。本-阿米·巴塔尔等人。然后将这些自由的老鼠暴露给他们从未见过或从未见过的陌生人。值得注意的是，老鼠一直在释放被困的陌生人，对待陌生人的行为就像对待熟悉的笼子一样。这一结果表明，个体的熟悉并不是帮助发生的必要条件。为了测试老鼠仁慈的限度，本-阿米·巴塔尔等人。用来自不同杂交品系的诱捕大鼠(黑帽大鼠)测试自由大鼠(总是白色白化大鼠)。老鼠帮助不同品系的笼子，但不能帮助不同品系的陌生人。这些结果可以用菌株熟悉度或个体熟悉度的要求来解释。为了区分这些可能性，白化大鼠被安置在不同品系的大鼠身上2周，然后与另一只白化大鼠重新安置，然后与另一只被困的不同品系的大鼠进行测试。与应变而不是个体熟悉的要求一致，自由的老鼠现在帮助陌生的老鼠从不同的但现在熟悉的菌株中分离出来。本-阿米·巴塔尔等人为了探索基因或亲缘关系在社会选择性帮助中是否起到了作用。仅根据基因关联，测试老鼠是否会帮助自己品系中的陌生人。为了做到这一点，白化幼鼠在出生当天被转移到不同品系的幼崽中，在测试之前，它们从未见过另一只白化小鼠，也没有与之互动过。值得注意的是，白化鼠帮助来自不同品系的陌生人，但它们没有帮助自己品系的陌生人，因为这种品系对它们来说是陌生的。事实上，帮助其他老鼠的动机源于社会互动，而不是遗传因素，这提供了它们在经常意外变化的社会环境中导航所需的灵活性。DOI：http://dx.doi.org/10.7554/eLife.01385.002
In mammals, helping is preferentially provided to members of one’s own group. Yet, it remains unclear how social experience shapes pro-social motivation. We found that rats helped trapped strangers by releasing them from a restrainer, just as they did cagemates. However, rats did not help strangers of a different strain, unless previously housed with the trapped rat. Moreover, pair-housing with one rat of a different strain prompted rats to help strangers of that strain, evidence that rats expand pro-social motivation from one individual to phenotypically similar others. To test if genetic relatedness alone can motivate helping, rats were fostered from birth with another strain and were not exposed to their own strain. As adults, fostered rats helped strangers of the fostering strain but not rats of their own strain. Thus, strain familiarity, even to one’s own strain, is required for the expression of pro-social behavior. DOI: http://dx.doi.org/10.7554/eLife.01385.001 Humans help family members and friends under circumstances where they may not help strangers. However, they also help complete strangers through both direct actions, such as helping someone who has stumbled, and indirect actions, such as giving to charity. Ben-Ami Bartal et al. have now explored the biological basis of such socially selective helping by testing whether rats help strangers, and if so, under what circumstances. In the experiments a free rat was exposed to another rat trapped inside a plastic tube with an outward-facing door for 12 one-hour sessions. When tested with a cagemate trapped inside the tube, most free rats learned within a few days to release the trapped rat by opening the door. Ben-Ami Bartal et al. then exposed the free rats to strangers they had never met or seen before. Remarkably the rats consistently released the trapped stranger, acting toward strangers just as they had acted toward familiar cagemates. This result suggested that individual familiarity is not required for helping to occur. To test the limits of rat benevolence, Ben-Ami Bartal et al. tested free rats (always white albino rats) with trapped rats from a different outbred strain (black-hooded rats). The rats helped cagemates of a different strain but not strangers of a different strain. These results could be explained by a requirement for strain familiarity or individual familiarity. To distinguish between these possibilities, albino rats were housed for 2 weeks with a rat of a different strain, and then re-housed with another albino rat before being tested with a trapped rat belonging to a different strain. Consistent with a requirement for strain but not individual familiarity, the free rats now helped stranger rats from the different, but now familiar, strain. To explore if there is any role for genetics or relatedness in socially selective helping, Ben-Ami Bartal et al. tested whether rats will help strangers of their own strain based on genetic relatedness alone. To do this albino pups were transferred to litters of a different strain on the day they were born, and never saw or interacted with another albino rat until testing. Remarkably, the albino rats helped strangers from the different strain that they were raised with, but they did not help strangers of their own strain because this strain was unfamiliar to them. The fact that the motivation to help other rats has its origins in social interactions rather than genetics provides the flexibility that is needed to navigate their way through social environments that often change unexpectedly. DOI: http://dx.doi.org/10.7554/eLife.01385.002