知觉学习对对比度适应的影响

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	知觉学习对对比度适应的影响
其他题名	The Effect Of Perceptual Learning On Contrast Adaptation
	董雪
	2015-05
摘要	适应(adaptation)和知觉学习(perceptual learning)都是对于人类生存来说重要的能力。适应指知觉系统能够根据所处的环境调整知觉状态，从而让我们能够以最佳的敏感度知觉周围的环境；知觉学习则使我们对所学习的事物形成优秀且持久的感知能力。针对二者的单独研究已有很多，在视知觉方面尤为细致和丰富，但是两者之间的相互关系仍然不清楚。本研究旨在探讨视知觉学习对对比度适应的影响及注意、任务范式、任务难度因素在其中的作用。研究一中，通过利用一种新的测量对比度阈限的方法——斜坡检测法(ramp detection method)重复了Greenlee, Georgeson, Magnussen, and Harris (1991)关于对比度适应后效影响因素的研究，证明斜坡检测方法能够有效测量对比度适应前后阈限大小，尤其在长时对比度适应后，能够有效追踪适应后效随时间的变化情况。研究二中利用四个实验探究了知觉学习对对比度适应的影响。首先使用了斜坡检测方法测量适应前后对比度阈限随着时间的变化，并研究经过6天对同一位置同一朝向光栅的对比度适应训练，适应后效如何变化。结果显示，对比度适应的训练显著降低了适应的后效，同时也减缓了适应后效的消退速率，这种学习效果能够显著地迁移到非训练的位置和光栅朝向上。研究二中的后续实验进一步表明，这一学习效应的产生并不是注意控制得到训练导致的。当训练前后测和训练中采用不同任务范式时，未发现训练导致的对比度适应后效变化。而提高任务难度虽然引起训练条件的对比度适应后效减弱，但学习效应未能向非训练条件迁移。本文研究中主要发现：斜坡检测任务能够有效测量对比度阈限及对比度适应后效消退进程；对比度适应训练能够显著降低适应后效及其恢复速率，这一学习效应具有一定的任务特异性，对于同种、难度较低的训练任务来说，学习效应可以相当大程度地跨视野跨朝向大范围的迁移，说明这种学习效应可能不仅发生在较早的脑区，也发生在较晚的脑区。另外，适应后效的降低可能与“习惯化”过程具有相同的神经机制。
其他摘要	Perceptual learning and adaptation are two crucial abilities for survival. daptationenables the visual system to adjust to the environment,such that we canperceive the world with superiorsensitivity. While, perceptual learning helps us develop better and long-lasting perceptual performance through training. Numerous studies have investigated daptation and perceptual learning in isolation. However, the relationship between these two types of brain plasticity remains largely unknown. In the present study, we have nvestigatedhow visual perceptual learning influences contrast adaptation and how this effect is affected by attention, the difficulty and similarity of training tasks. In Experiment 1, by replicating Greenlee et al.’s(1991)workabout how contrast adaptation is affected by factors such as adapting contrast and adapting duration, we verified that our new method, termed ramp detection, is valid for tracking the time course of contrast threshold after adaptation especially in higher adapting contrast and longer adapting duration conditions. In Experiment 2, by virtue of this newmethod, we investigated whether and how the effects of contrast adaptation can be modulated by 6 days of training to adapt to a high contrast pattern. The results indicated that training on contrast adaptation reduced the immediate adaptation effectand its rate for decaying to an unadapted baseline. This learning effect transferred to orthogonal positions and orientation which was untrained during the experiment. The reduced adaptation effect and rate of decay was not induced from the training on attention control system, rather, it might because of the training on adaptation. When using different paradigm in pre-, post-test and training, we were not able to find a reduced adaptation effect after training. Moreover, the transfer of learning decreased if trainedwith a more difficult task. The main findings in current study are a) ramp detection method is effective to track the time courseof contrast threshold before and after adaptation, b) contrast adaptation could be weakened after training, the learningeffect is relatedto training taskand task difficulty, as to aneasy training task, the learning effect could transfer significantly to orthogonal untrained locations and orientations. Thus indicated that learning may occur not only at low level brainareabut also some high level areas, also, theadaptation may be modified by perceptual learning through mechanisms shared with another biological phenomenon, habituation.
学科领域	应用心理学
关键词	对比度适应斜坡检测方法知觉学习注意
学位类型	硕士
语种	中文
学位专业	心理学
学位授予单位	中国科学院研究生院
学位授予地点	北京
文献类型	学位论文
条目标识符	http://ir.psych.ac.cn/handle/311026/19505
专题	社会与工程心理学研究室
作者单位	中国科学院心理研究所
推荐引用方式 GB/T 7714	董雪. 知觉学习对对比度适应的影响[D]. 北京. 中国科学院研究生院,2015.

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