Stimulus preexposure effects and associative learning

心理学家想要了解个体适应/个体有机体与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得不同。这个过程（通常称为学习）可以在实验室中用非人类动物进行有效研究，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（使用由俄罗斯生理学家巴甫洛夫引入的一种被称为条件反射的过程）已经确定，许多学习可以用环境中一起发生的事件之间（或者更准确地说，事件的中心表征之间）的联系（或关联）的形成来解释。因此，学习依赖于动物体验成对的刺激。联想原理在我们的学习观念中占据主导地位至少有一百年了。然而，最近人们越来越清楚，一种重要的学习形式可以在没有配对的情况下进行。人们早就知道，简单地暴露在单一的刺激下会产生一种习得的行为改变（这种现象被称为习惯化），最明显的表现是最初由刺激引起的反应减弱。但事实证明，这个过程会产生更复杂、更有趣的结果。预暴露刺激不仅会降低刺激唤起正常反应的能力，还会改变刺激正常运作的能力，当涉及到联想形成/当配对刺激中的任何一个被预暴露时，联想形成进展缓慢。此外，动物区分类似刺激的能力在预先暴露后似乎得到了增强。这个项目的目的是阐明导致这些预曝光效应的学习的本质。实验的出发点是观察到预暴露对后续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/具体地说，预暴露产生的影响在目标刺激之前或之后，在预暴露阶段有一些其他事件。在预暴露过程中，目标刺激预测的内容或其本身预测的好坏决定了过程的结果。是什么学习过程导致了这一点？这些实验将调查一个假设，即实际上涉及两个学习过程。其中之一（负责简单的习惯化现象）在预暴露期间减少刺激的有效显着性（就好像大声的噪音在重复呈现后逐渐变得有效柔和）。我们的实验将探讨在预暴露过程中，当目标刺激单独呈现（或与恒定的关联）时，这一过程运行得最好，但当目标刺激被一些其他事件不可靠地预测时，这一过程可能会逆转。第二个过程是改变对刺激的关注的某些方面（与突出性不同/显然有可能学会注意轻微的噪音，甚至可能学会忽略大声的噪音）。我们的实验将探索这样一种观点，即动物学会关注结果不确定的刺激，但最终学会减少对结果不一致的刺激的关注。我们对这些接触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基本心理重要性的机制，我们才认为有必要详细探讨决定联想机制运作的附属学习过程。

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.