Luu Tina, Howe Piers D L
School of Psychological Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
Atten Percept Psychophys. 2015 Aug;77(6):1919-29. doi: 10.3758/s13414-015-0891-8.
There is much debate regarding the types of information observers use to track moving objects. Howe and Holcombe (Journal of Vision 12(13): 1-10, 2012) recently reported evidence that observers employ extrapolation while tracking. However, their study is potentially confounded because it did not control for eye movements. As eye movements can aid extrapolation, it is unclear whether extrapolation can still occur in multiple object tracking (MOT) when eye movements are eliminated. In the current study, we addressed this question using an eye tracker to ensure that fixation was always maintained on a central fixation point while observers performed a tracking task. In the predictable condition, objects always travelled along linear paths. In the unpredictable condition, objects randomly changed direction every 300-600 ms. If observers employ extrapolation, we would expect performance to be greater in the former condition than in the latter condition. Our results showed that observers did indeed perform better in the predictable condition than in the unpredictable condition, at least when tracking just two objects (Experiments 1, 3, and 4). Extrapolation occurred less when tracking loads increased or when the objects moved more slowly (Experiment 2).
关于观察者用于追踪移动物体的信息类型存在诸多争议。豪和霍尔科姆（《视觉杂志》12(13): 1 - 10, 2012）最近报告了观察者在追踪时采用外推法的证据。然而，他们的研究可能存在混淆因素，因为没有控制眼球运动。由于眼球运动有助于外推法，所以当消除眼球运动时，外推法在多目标追踪（MOT）中是否仍会发生尚不清楚。在当前研究中，我们使用眼动仪解决了这个问题，以确保在观察者执行追踪任务时，注视点始终保持在中央固定点上。在可预测条件下，物体总是沿直线路径移动。在不可预测条件下，物体每300 - 600毫秒随机改变方向。如果观察者采用外推法，我们预计在前一种条件下的表现会优于后一种条件。我们的结果表明，观察者在可预测条件下的表现确实优于不可预测条件，至少在追踪仅两个物体时（实验1、3和4）。当追踪负荷增加或物体移动更慢时，外推法出现的情况较少（实验2）。
