Stimulus preexposure effects and associative learning

心理学家希望了解个体适应/个体有机体与其环境相互作用的过程，通过相互作用而改变，然后在未来的相互作用中表现出不同的行为。这个过程（通常被称为学习）可以在实验室中用非人类动物进行有效的研究，这些动物的环境经验可以被仔细控制，其行为可以被严格记录和测量。这些研究（使用了俄罗斯生理学家巴甫洛夫（Pavlov）提出的条件反射（conditioning）程序）已经证实，许多学习可以用在环境中一起发生的事件（或者更准确地说，事件的中心表征之间）之间的联系（或关联）的形成来解释。因此，学习依赖于动物经历成对的刺激。联想原则在我们的学习观中占主导地位至少有一百年了。然而，最近人们发现，一种重要的学习形式可以在没有配对的情况下发生。人们早就知道，简单地暴露于单一刺激会产生行为上的习得性变化（称为习惯化的现象），这最清楚地表现为最初由刺激引起的反应的减弱。但这个过程产生了更复杂和有趣的后果。预先暴露于刺激不仅降低了其唤起正常反应的能力，还改变了刺激在联想形成时正常发挥作用的能力/当成对刺激中的任一个被预先暴露时，联想形成进展缓慢。此外，动物的能力，以区分类似的刺激似乎是增强时，这些已预先暴露。这个项目的目的是阐明学习的性质，负责这些暴露前的影响。实验的出发点是观察到预暴露对随后的联想学习的影响可以通过预暴露期间其他事件的存在来调节/特别是，预暴露产生的影响在目标刺激之前或之后是预暴露阶段期间的一些其他事件。在预暴露过程中，目标刺激预测了什么，或者它本身预测得有多好，决定了程序的结果。是什么样的学习过程导致了这一点？实验将调查的假设，事实上，两个学习过程。其中之一（负责简单的习惯化现象）在预暴露期间产生刺激的有效显着性降低（就好像一个响亮的噪音随着重复呈现而逐渐变得有效地柔和）。我们的实验将研究的建议，这一过程的运作最好的时候，目标刺激单独（或与一个恒定的关联）在预曝光，但可以逆转时，目标刺激预测不可靠的一些其他事件。第二个过程是改变对刺激的注意力的某个方面（与显著性不同的东西/很明显，学习注意一个柔和的噪音是可能的，甚至可能，学习忽略一个响亮的噪音）。我们的实验将探索这样一种观点：动物学会注意一种结果不确定的刺激，但最终学会减少对一种结果不一致的刺激的注意。我们对这些确定性学习过程的兴趣并不意味着我们要否认联想学习本身的核心重要性。相反，正是因为我们认为联想学习是一种具有根本心理重要性的机制，所以我们认为有必要详细探讨决定联想机制运作的辅助学习过程。

Psychologists want to understand individual adaptation / the process by which an individual organism interacts with its environment, is changed by the interaction, and is then equipped to behave differently in future interactions. This process (commonly referred to as learning) can be effectively studied in the laboratory with nonhuman animals whose environmental experience can be carefully controlled and whose behaviour can be rigorously recorded and measured. Such studies (using a procedure known as conditioning, introduced by the Russian physiologist Pavlov) have established that much learning can be explained in terms of the formation of links (or associations) between events (or more correctly, between the central representations of events) that occur together in the environment. Learning thus depends on the animal experiencing pairings of stimuli. The associative principle has dominated our view of learning for at least a hundred years. More recently, however, it has become clear that an important form of learning can occur without pairings. It has long been known that simple exposure to a single stimulus will produce a learned change in behaviour (the phenomenon known as habituation), which shows most clearly as the waning of the response initially evoked by the stimulus. But this procedure turns out to have more complex and interesting consequences. Preexposure to a stimulus not only reduces its ability to evoke its normal response, it also changes the ability of the stimulus to function normally when it comes to association formation / association formation proceeds slowly when either of the paired stimuli has been preexposed. In addition, the animal's ability to discriminate between similar stimuli appears to be enhanced when these have been preexposed. The aim of this project is to elucidate the nature of the learning that is responsible for these preexposure effects. The starting point for the experiments is the observation that the effects of preexposure on subsequent associative learning can be modulated by the presence of other events during preexposure / specifically, the effects produced by preexposure differ in the target stimulus is either preceded or followed by some other event during the preexposure phase. What the target stimulus predicts or how well it is itself predicted during preexposure determines the outcome of the procedure. What learning process is responsible for this? The experiments will investigate the hypothesis that in fact two learning processes are involved. One of them (that responsible for the simple habituation phenomenon) produces a reduction in the effective salience of the stimulus during preexposure (as if a loud noise gradually becomes effectively softer with repeated presentation). Our experiments will investigate the suggestion that this process operates best when the target stimulus is presented alone (or with a constant associate) during preexposure, but can be reversed when the target stimulus is predicted unreliably by some other event. The second process is one that changes some aspect of the attention paid to a stimulus (something distinct from salience / it is clearly possible to learn attend to a soft noise, and even, possibly, to learn to ignore a loud one). Our experiments will explore the suggestion that animals learn to attend to a stimulus the consequence of which are uncertain, but learn, eventually, to reduce the attention paid to one followed by inconsistent consequences. Our interest in these exposure-learning processes does not mean that we want to deny the central importance of associative learning itself. To the contrary, it is because we think that associative learning is a mechanism of fundamental psychological importance that we think it necessary to explore in detail the subsidiary learning processes that determine the operation of the associative mechanism.