Rats and other animals need to be highly attuned to social signals from others so they can identify friends to cooperate with and enemies to avoid. To find out if this extends to non-living beings, Laleh Quinn at the University of California, San Diego, and her colleagues tested whether rats can detect social signals from robotic rats.

    They housed eight adult rats with two types of robotic rat—one social and one asocial—for four days. The robot rats were quite minimalist, resembling a chunkier version of a computer mouse with wheels to move around and colorful markings.

    During the experiment, the social robot rat followed the living rats around, played with the same toys, and opened cage doors to let trapped rats escape. Meanwhile, the asocial robot simply moved forwards and backwards and side to side.

    Next, the researchers trapped the robots in cages and gave the rats the opportunity to release them by pressing a lever.

    Across 18 trials each, the living rats were 52 percent more likely on average to set the social robot free than the asocial one. This suggests that the rats perceived the social robot as a genuine social being. They may have bonded more with the social robot because it displayed behaviours like communal exploring and playing. This could lead to the rats better remembering having freed it earlier, and wanting the robot to return the favour when they get trapped, she says.

    The readiness of the rats to befriend the social robot was surprising given its minimal design. The robot was the same size as a regular rat but resembled a simple plastic box on wheels. “We’d assumed we’d have to give it a moving head and tail, facial features, and put a scent on it to make it smell like a real rat, but that wasn’t necessary,” says Janet Wiles at the University of Queensland in Australia, who helped with the research.

    The finding shows how sensitive rats are to social cues, even when they come from basic robots. Similarly, children tend to treat robots as if they are fellow beings, even when they display only simple social signals. “We humans seem to be fascinated by robots, and it turns out other animals are, too,” says Wiles.

答案精析：本题为推断题。根据题文同序原则可定位至原文结尾。最后一段首句提到，这一发现表明，老鼠对社交信号非常敏感，即使这些信号来自最初级的机械鼠。最后一句也指出，我们人类似乎对机器人很着迷，而事实证明其他动物也一样。结合前文提到的，研究人员原本以为要给机械鼠安装一些装置或添加气味来使它看起来更逼真，但事实证明，没有这些，老鼠也能识别机械鼠发出的社交信号。由此可推知，老鼠对社交信号的敏感程度比研究人员预期的要高，故正确答案为D项。

错项排除：A项中的new surroundings在原文中没有依据，故排除。B项利用原文最后一句中的other animals进行干扰，但原文说的是其他动物和人类的相似性，并没有说老鼠在社交上会比其他动物更活跃，故B项错误。C项利用children进行干扰，但原文说的是，孩子们同样也会倾向于把机器人当成同类，即使它们只发出了简单的社交信号，这里的重点是老鼠和孩子在识别社交信号方面具有相似性，并非不同，故C项错误。