目标与非目标数量变化对多目标追踪的选择性抑制效应

The Selective Inhibition Effects of Changing the Number of Targets and Nontargets on Multiple Object Tracking

采用多目标追踪和点探测刺激觉察任务相结合的实验范式,考察目标和非目标数量变化对多目标追踪的选择性抑制效应。实验一设置非目标恒定而变化目标数量,结果发现:随着目标数量的增加,目标与非目标间的抑制差异量不随目标数量变化而变化。实验二设置目标恒定而变化非目标数量,结果发现:在非目标数量变化的三种水平下,目标与非目标间的抑制差异量也无显著差异。综合实验结果表明:在多目标追踪的追踪容量或抑制容量范围内,抑制差异量对目标数量或非目标数量变化是不敏感的;注意资源分配方式在一定范围内保持相对稳定。

Previous studies have proved that there is a highly localized object-based inhibition on nontargets in the Multiple Object Tracking（MOT） task.And researches have studied the mechanism of selective nontarget inhibition mainly through operating the characteristic contrast between non-targets and targets such as moving pattern,shape and stereo disparity,while the number of targets and nontargets stayed constant.Using the Multiple Object Tracking with Probe Dot Detection task,the present study examined selective inhibition effects in Multiple Object Tracking with the number of targets or nontargets changed. Two experiments were conducted and both were a 3×2 within-subject design.The two independent variables were targets＇ number （Experiment 1,subjects tracking 2,3 or 4 targets while there were 5 nontargets ） or nontargets＇ number（Experiment 2,having 4,6 or 8 nontargets while there were 4 targets） and probe dot locations（probe dot presented in a target or nontarget）.During the experiments, the subjects must track the targets and monitor if a probe dot was presented in the objects（targets or nontargets）.Subjects＇ tracking accuracy and probe detection performance on targets and nontargets were recorded as dependent variables. The results showed that in both experiments,tracking accuracy decreased as the number of targets or nontargets increased.And probe detection performance on targets was significantly better than that on nontargets,which meant that the nontargets were effectively inhibited during tracking.In Experiment 1,as the number of targets increased,the probe dot detection performance on targets and nontargets both decreased,but the amounts of differences in inhibition between the targets and nontargets remained stable,not varying with the number of targets.The results of Experiment 2 showed that the probe dot detection performance on targets and nontargets remained relatively constant when the number of nontargets changed among 4,6,or 8.The degrees of differences in inhibition between the targets and nontargets were not significantly different among the three conditions varying in the number of nontargets,either.Finally,the average degrees of differences in the inhibition of Experiments 1 and 2 were not significant. Because the maximum number of targets and non-targets in Experiments 1 and 2 was supposed to be within participants＇ tracking and inhibiting capacity,the findings of the present study suggested that in Multiple Object Tracking the degrees of differences in inhibition were not sensitive to the number of targets or nontargets.And within a certain range,the attention resources allocated to targets and nontargets remained relatively stable in Multiple Object Tracking.