词汇的情绪效价对语义饱和效应的影响

词汇的语义饱和效应是指,多次重复感知或产生一个词汇时,主观上对该词汇的意义的暂时缺失现象。本研究通过两个实验考察了词汇的情绪效价对语义饱和进程的影响。实验1旨在探讨快速类别匹配范式是否可以用来考察语义饱和效应。本实验采用了与Tian和Huber（2010）实验中类似的材料,但排除了同一对刺激中正性和负性范例混合的情景。材料包括11个类别,每一类选择20个该类别的具体范例（如“蔬菜”类别下包括“土豆”、“茄子”等）,所有范例词汇都是双字词。每个被试完成11个任务组块。在每个组块中,有20个试次,其中10个试次是重复类别条件,另10个试次是非重复类别条件。一半的范例对来自同一类别（即匹配试次）,另一半由不同类别（即非匹配试次）的范例组成。24名大学生观看启动范例词（如“土豆”）和目标范例词（如“茄子”）,判断启动词和目标词是否来自同一个类别。结果显示,在第一个时间片段内（第2-4个试次）,重复条件的反应时显著快于非重复条件,而在第二段（第5-7个试次）和第三段（第8-10个试次）两者没有显著差异。这表明,在控制词汇情绪效价的情况下,快速类别匹配范式可以成功引起语义饱和效应。基于此,实验2采用快速类别匹配范式考察情绪效价对词汇语义启动效应进程的影响。72名被试被随机分为三组,分别使用正性、中性和负性词汇材料。对于每一种情绪效价,均选择了11个类别,如正性类别“花”和负性类别“疾病”。每一类别选择了20个双字词范例词汇。每一类别的实验设计和过程同实验1。结果表明,积极词的语义饱和效应出现在较晚试次中（第8-10个试次）,中性词的语义饱和效应出现在中间试次中（第5-7个试次）,而消极词则没有出现显著的语义饱和效应。该结果表明,词汇的情绪效价能调节语义饱和的时间进程。这提示,未来的语义饱和效应研究应该考虑实验材料的情绪效价。     

Intentional attention switching in dichotic listening: Exploring the efficiency of nonspatial and spatial selection

Using an auditory variant of task switching, we examined the ability to intentionally switch attention in a dichotic-listening task. In our study, participants responded selectively to one of two simultaneously presented auditory number words (spoken by a female and a male, one for each ear) by categorizing its numerical magnitude. The mapping of gender (female vs. male) and ear (left vs. right) was unpredictable. The to-be-attended feature for gender or ear, respectively, was indicated by a visual selection cue prior to auditory stimulus onset. In Experiment 1, explicitly cued switches of the relevant feature dimension (e.g., from gender to ear) and switches of the relevant feature within a dimension (e.g., from male to female) occurred in an unpredictable manner. We found large performance costs when the relevant feature switched, but switches of the relevant feature dimension incurred only small additional costs. The feature-switch costs were larger in ear-relevant than in gender-relevant trials. In Experiment 2, we replicated these findings using a simplified design (i.e., only within-dimension switches with blocked dimensions). In Experiment 3, we examined preparation effects by manipulating the cueing interval and found a preparation benefit only when ear was cued. Together, our data suggest that the large part of attentional switch costs arises from reconfiguration at the level of relevant auditory features (e.g., left vs. right) rather than feature dimensions (ear vs. gender). Additionally, our findings suggest that ear-based target selection benefits more from preparation time (i.e., time to direct attention to one ear) than gender-based target selection.