练习过一段时间SAT阅读的同学都习惯边读边划出前人理论或过去实验结论，但并不清楚为什么要这样做。这些就是SAT阅读中的前人研究，那它究竟是什么呢？今天，小编就为大家解释一下。

      1.前人研究 = 作者论点的证据

      这是大家都比较熟悉的一种逻辑；考试中出现频率也；最常见结构是作者先说明自己的观点，然后补充前人研究、过去实验结果、或者引用专家证言作为支持。比如：

      However, political cyber-optimists have criticized cyberpessimists for being too extreme and maintain that new media might be the decisive element in pushing the democratic agenda of elections nowadays. For instance, based on data published by the Pew Research Center, sixty-six percentage of social media users have participated in at least eight online political activities, such as encouraging people to vote or posting their comments on politics through social media. Thus, Internet voters may shape election campaign agendas to some extent.

      在这个例子中，作者引用Pew Research Center的调研结果，证明过半数网络用户参与过政治活动、直接证明“新媒体是现今影响选举的决定性因素”。这种逻辑中，作者观点和前人研究是一种极其具体的对应关系 —— 只认识到Pew Research Center的调查证明参与过政治活动的网民人数很多、或者只认识到这个研究能够证明作者观点都是不够的、应该把“new media might be the decisive element”和“Internet voters may shape election campaign agendas to some extent”直接对应起来才真正理解了二者之间证明与被证明的关系。

      2.前人研究 = 新研究的前提（premise）

      这种逻辑有时会被读者忽视，但实际上是一种很重要、很常见的学术逻辑。学术研究实际上就是一个综述过去研究成果、从中定位待决问题、通过特定方法解决问题的过程。学术写作过程中，应该先指出前人在这方面已经进行了哪些研究、有何成果、对现在研究有何影响；换言之，前人研究和观点就是现在研究的前提。具体而言，研究前提又有两种常见作用：

      In 2003 Sinclair's lab published a paper in Nature that described the discovery of a gene that switched on in the yeast cell in response to calorie restriction, which Sinclair calls a "master regulator in aging." Since then, his team has been searching for an analogous gene that plays a similar role in the mammalian cell.

      The researchers determined from cultures of human embryonic kidney cells that lower caloric intake sends a signal that activates a gene inside cells that codes for the enzyme NAMPT (nicotinamide phosphoribosyl-transferase). The two to four-fold surge in NAMPT in turn triggers the production of a molecule called NAD (nicotinamide adenine dinucleotide), which plays a key role in cellular metabolism and signaling.

      这篇文章研究重点在于减少热量摄入能否延长寿命。作者之所以引入2003年实验，是在指出预期结论（减少热量能延缓衰老）已经在酵母细胞实验中得到验证。换言之，如果酵母细胞实验没有得到预期结论，也就没有使用哺乳动物细胞进行进一步实验的必要；因此之前研究和现在研究结果是平行关系，新结果是旧结果改变某个变量（yeast cell → mammalian cell）得来的。

      Dr. Johnson knew from his own past work that when broad-bean plants are attacked by aphids they respond with volatile chemicals that both irritate the parasites and attract aphid-hunting wasps. He did not know, though, whether the message could spread from plant to plant. So he set out to find out-and to do so in a way which would show if fungi were the messengers.

      The passage suggests that in designing the experiment, Johnson relied on the fact that

      A) fungal hyphae warn beanstalks of danger if a nearby plant is attacked.

      B) wasps are harmful to the ongoing existence of broad bean plants.

      C) broad bean plants release noxious chemicals to ward off infestation.

      D) aphids are able to withstand the aggressive maneuvers used by wasps.

      这道2018年考题代表另一种常见逻辑 – 前人研究结果决定现在研究的实验方法(methodology). 实验者想研究植物能否传递受感染的信号；可以设计实验检测未受感染的植物会不会自动释放刺激物 – 如果释放、说明它们能从某处接受信号，反之证明不能。这个实验之所以可以这样设计，正是利用了植物受到蚜虫感染时会释放刺激物这一特点，而这一特点来源于之前研究，答案选C）。

      3.前人研究 = 错误认识

      这种逻辑在SAT阅读中只是偶尔出现，常见结构是作者描述一种先前存在的观点/理论、然后对其进行反驳，实际上是一种观点的转折（阅读中观点转折总是很重要）。作者使用这种逻辑、实际上是想通过驳斥一种普遍观点来突出新研究的重要性。比如：

      The brain is a mutable organ, capable — within limits — of reorganizing itself and readapting to new kinds of sensory input, a phenomenon known as neuroplasticity. It had long been thought that the adult brain was incapable of spawning new neurons—that while learning caused synapses to rearrange themselves and new links between brain cells to form, the brain’s basic anatomical structure was more or less static. Maguire’s study suggested the old inherited wisdom was simply not true.

      According to the passage, Maguire’s findings regarding taxi drivers are significant because they

      A) demonstrate the validity of a new method.

      B) provide evidence for a popular viewpoint.

      C) call into question an earlier consensus.

      D) challenge the authenticity of previous data.

      这篇文章中，作者明知过去的理论是错误的、还要特意强调“前人共识是大脑不能发生结构上的改变”，就是想强调Maguire研究成果的重要意义；答案选C）.

      最后要强调的是，单纯理论上理解这些逻辑结构是远远不够的。要提高初读文章的效率，要在平时练习中不停反思、分析文章逻辑，才能在正考中迅速抓住前人观点和作者观点间的关系；准确定位出题点。

      更多SAT高分技巧尽在杭州新航道，详情可咨询在线老师，也可以直接联系杨老师：17757149597。