【作者】 陈晶；

【导师】 沈模卫；

【作者基本信息】 浙江大学 ， 基础心理学， 2010， 硕士

【摘要】 视觉工作记忆是当前认知心理学的研究热点之一。目前视觉工作记忆的研究主要集中在存储容量和存储方式上,鲜有研究涉及视觉工作记忆的客体表征形式这一基本问题。在认知科学领域,客体的表征主要有位图式和矢量式两种形式,位图式表征直接存储图像每个点的信息,图像越大所占存储空间越大；矢量式表征存储描述图像属性的抽象指令,其存储空间对图像的大小并不敏感。探明客体以何种形式表征的问题,不仅有助于加深对视觉工作记忆的内部机制的理解,而且对智能机器人感知系统的设计具有指导意义。本研究通过考察几何图形的大小是否影响工作记忆的存储精度,以探讨视觉工作记忆的客体表征形式究竟属位图式抑或是矢量式的问题。本研究包括以下四个实验：实验一采用主观调节范式,通过操作大小不同的圆形刺激,比较其在视觉工作记忆中的记忆精度,检验其表征形式是位图式抑或是矢量式。实验二以反映视觉工作记忆存储过程的CDA为指标,比较了圆形的大小是否影响其在工作记忆中的存储绩效。实验三选用不规则四边形作为刺激材料,以排除由刺激的特殊性所造成的干扰,对实验一的结果进行进一步检验。实验四要求被试同时记忆不规则四边形的大小和形状,提高任务难度,以检验实验一的结果是否具有跨实验任务难度的一致性。本研究得到以下主要结果：(1)简单图形和复杂图形的大小对记忆绩效均无影响；(2)图形的大小对CDA的幅值无影响；(3)随着记忆项目数的增加,记忆绩效的下降不因图形大小而有差异。基于上述结果,可以认为,几何图形在视觉工作记忆的表征形式属矢量式表征。更多还原

【Abstract】 Visual Working Memory (VWM) is a popular research question in cognitive psychology. Most of the current work concerning VWM focuses on its capacity and the approaches of storage; however, few studies have attended to the form of object representations in VWM, which is a fundamental question in the field. In cognitive science, there are two main forms of object representations:raster representation and vector representation. The raster representations are built up from pixel-like information of objects, by which a bigger object occupies more storage resources compared to smaller one. In contrast, the vector representations are composed of abstract primitives describing object properties, and the consuming storage resources are insensitive to the size of objects. To clarify the way how objects are represented in VWM can not only help to enhance the understanding of the inherent mechanism of VWM, but also is instructive to the design of cognitive system of intelligent robots.Aimed to explore whether the representations of objects in VWM is vector or raster, this study tested whether size of geometrical figures influences the storage of VWM. Four experiments were conducted. Adopting subjective adjusting paradigm, Experiment 1 compared memory precision of circles with different sizes in order to examine whether the size of object would affect its representation. Experiment 2 surveyed whether the size of circles would affect memory performance, by taking Contralateral Delay Activity (CDA) as an index to reflect the representation maintenance in VWM. The change detection paradigm was employed. In addition, Experiment 3 applied irregular polygons as stimuli intending to rule out the possible irrelevant effect caused by the particularity of using circles as stimuli. Finally in Experiment 4, whether the results could be generalized to varied task difficulties was overviewed by asking the observers to memorize both color and size of irregular polygons in the change detection task.The main findings are as follows:(1) The memory performances in VWM are not affected by the size of objects, no matter simple or complex. (2) Neither the corresponding CDA amplitude is influenced by the size. (3) The memory precision decreases when set size increases and the decline is indifferent for bigger or smaller objects.In conclusion, the findings are supporting the perspective of vector representation of geometric figures.更多还原