Acquisition of Predictable Vertical Visual Targets: Eye-Head Coordination and the Triggering Effect

The study was designed to investigate target acquisition in the vertical plane with emphasis on establishing strategy differences associated with acquisition triggering methods. Eight subjects were tested. Measurements consisted of target acquisition time, eye-head latency differences, velocity of gaze, eyes and head, and head amplitude. Using 3-way repeated measures analyses of variance the results show that the strategy for acquisition of predictable visual targets in vertical plane with the head unrestrained significantly depended on (a) the direction of the gaze motion with respect to the gravity vector (i.e., there is significant up-down asymmetry), (b) the angular distance of the target, and (c) the method of triggering the command to acquire the target—external versus internal. The data also show that when vertical acquisition is compared with triggering methods in the horizontal plane there is a difference in overall strategy for the acquisition of targets with the same spatial distances from straight ahead gaze when both the eyes and head are used. Among the factors contributing to the difference in strategy for vertical target acquisition are the gravitational vector, the relationship of target displacement and vestibular activitation, biomechanical and neural control asymmetries, and the difference in the vertical field of view.     

不同预测率的不确定决策的ERP研究

该研究采用事件相关电位技术,对不同预测率的不确定决策的加工机制进行了研究。实验条件为四种不同预测率的不确定决策任务,控制条件为确定决策任务,对两种条件下的数据进行比较,结果发现：1）反应时,随着不确定性程度的增强而逐渐增长;2）正确率,被试决策的平均正确率基本上符合数字本身的可预测率。脑电结果发现：在200～300ms的时间窗口内,不确定和确定决策任务下的预测率都诱发了一个晚期的负成分（N2）,五种任务之间（随着不确定程度的降低）存在着一个梯度的变化,其中50％和62．5％之间不存在着显著差异,其它预测率之间都存在着显著差异。这些结果表明被试在不确定决策任务中会对不同预测率进行归类表征,并会对不同的不确定程度有不同的知觉。