内源性注意与外源性注意神经机制的渐合假说
其他题名The convergence hypothesis of endogenous and exogenous attention
王妍
学位类型博士
导师罗跃嘉
2009-06-01
学位授予单位中国科学院心理研究所
学位授予地点心理研究所
关键词内源性注意 外源性注意 事件相关电位(ERP) 老龄化 知觉负荷
摘要内源性注意与外源性注意神经机制的关系至今存在争论,通过对前人研究成果的总结和一系列实验研究,对两类注意神经机制的关系提出了新的见解,并归纳为“渐合假说”或模型。 许多研究者认为内源性注意和外源性注意是两个独立的系统,这两个不同的系统对加工不同类型的刺激、适应复杂多变的环境起着特定而重要的作用。也有研究发现内源性注意和外源性注意激活了一些共同的脑区,这些兴奋区域在功能上是否也存在共同作用还需要进一步的研究证明。以往用于描述内源性注意和外源性注意神经机制关系的模型相对比较绝对化,没有深入说明这两类注意在加工过程中的关系,而且多数对内源性和外源性注意的研究都是割裂开来进行的。 我们的研究采用“提示-靶”实验范式,通过控制提示物与靶之间的时间间隔和提示物的有效提示率来区别内源性和外源性注意。我们的ERP和行为实验发现在注意加工的初始阶段这两类注意的差别较大,在外源性注意中相对于被无效提示的靶,被有效提示的靶诱发更大的P1成分波幅和更小的N1波幅,内源性注意条件下,相对于被无效提示的靶,被有效提示的靶诱发更大的P1、N1波幅。用内源性注意的有效提示条件减去外源性注意的有效提示条件,得到两类注意的差异波,初始阶段的波形差异显著,而后差异逐渐减小。在本研究中我们分析了内源性注意与外源性注意神经机制的相互关系,观察到这两类注意机制不应该是完全独立的系统,它们在加工的初始阶段是分离的,但是随着加工的深入,两类注意趋于一致,是一个动态的过程。由此我们认为,新异刺激会激活外源性注意加工过程中的“外触发器”,使信息向上传递;在内源性注意加工过程中,当观察者“想注意”时会激活“内触发器”,使信息向下传递。内源性注意和外源性注意机制在“外触发器”和“内触发器”上的差异较大,表现为早期加工阶段的差别比较明显。当刺激信号进入到下一个加工阶段的时候,也就是注意指向性和集中性的后期加工阶段,差异减小,加工过程有逐渐合并的趋势。这就是说,在加工时间进程上,这两类注意的加工是一个由分到合的“渐合”过程。 在不同知觉负荷条件下用相继呈现内源性注意和外源性注意的实验范式考察这两种注意机制之间的相互关系。结果从差异波上可以看到,无论是在高知觉负荷还是在低知觉负荷条件下,初始阶段的波形差异较大,而后逐渐趋于平缓,说明在不同知觉负荷条件下,内源性注意和外源性注意机制的关系都符合“渐合”概念。此外我们还观察到在不同的知觉负荷条件下两类注意机制的关系存在一定的差别,说明知觉负荷对“外触发器”和“内触发器”存在一定的调节作用。 在年龄和知觉负荷对注意影响的实验中,我们对比年轻组和老年组在不同知觉负荷条件下的注意效应,结果发现老年组的反应时上比年轻组长,在ERP成分上,年龄效应主要反映在N1成分上,老年组的波幅大于年轻组,在高知觉负荷条件下年龄效应更加明显。这就是说,注意能力随年龄的增长而衰退,老年人需要更多的注意资源完成任务。相对于内源性注意,在外源性注意中,年龄和知觉负荷对注意的影响更加明显,说明年龄对注意加工过程中的外触发器和内触发器存在影响。 综上所述,本研究通过对内源性注意和外源性注意机制的研究提出了“渐合假说”,并探讨了知觉负荷和年龄对该注意机制的影响。
其他摘要The relationship between exogenous attention and endogenous attention is still unclear. We conclude the result of previous studies and our experiments by proposing a convergence hypothesis. A lot of evidences from ERP and fMRI proved the distinction between exogenous and endogenous attention. The distinction is fit for the complicated surroundings. Some studies found that exogenous and endogenous attention activated some common brain areas but if there’s any common function in these areas was still unclear. Previous studies failed to disentangle the relationship between these two mechanisms in detail, and most of the previous studies compared these two mechanisms separately. We used the cue-target paradigm, controlled the SOA and the cue validity to separate endogenous and exogenous attention. We try to figure out the relationship between endogenous and exogenous attention. We found that, in the exogenous attention condition, the amplitude of the P1 component was larger and the amplitude of N1 was smaller than that in the invalid trials. In the endogenous attention condition, the amplitudes of the P1 and N1 components in valid trials were both larger than that in the invalid trials. The difference wave of endogenous and exogenous attentions showed that at the beginning of their process endogenous and exogenous attentions were separate and then the process was going to converge. The stimuli appear in the visual field will activate the “external trigger” in exogenous attention processing, and then the signal will be transferred to next stage, in the endogenous attention processing, when the observer want to attend, the “inner trigger” will be activated and the signal will be transfered. The difference between “external trigger” and “inner trigger” in endogenous and exogenous attention was significant, so the difference at the beginning of the process was significant. When the signal was transferred to the next processing stage, the difference between the endogenous and exogenous attention became diminished, and it was a convergence process. We used the cue-target paradigm, let the central cue and peripheral cue appear in one trial, try to investigate the relationship between endogenous and exogenous attention under different perceptual load conditions. The result from of difference wave showed that the relationship between the two attentions was consistent with the convergence hypothesis. We also found that under different perceptual load conditions, the relationship between endogenous and exogenous attention was different. The perceptual load has influence on the “external trigger” and “inner trigger”. A cue-target paradigm was used to investigate the relationship between attention, age and perceptual load, we found that the function of visual attention was decrease in the old group, they need more attentional resource when they face the issue. The aging effect has influence on the “external trigger” and “inner trigger”. The effects of age and perceptual load were much higher in exogenous attention condition.
页数105
语种中文
文献类型学位论文
条目标识符http://ir.psych.ac.cn/handle/311026/4656
专题中国科学院心理研究所回溯数据库(1956-2010)
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GB/T 7714
王妍. 内源性注意与外源性注意神经机制的渐合假说[D]. 心理研究所. 中国科学院心理研究所,2009.
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