Chen Wei-Ying, Howe Piers D, Holcombe Alex O
School of Psychology, University of Sydney, Brennan MacCallum Bldg (A18), Sydney, New South Wales 2006, Australia.
Atten Percept Psychophys. 2013 May;75(4):710-25. doi: 10.3758/s13414-013-0425-1.
The attentional processes for tracking moving objects may be largely hemisphere-specific. Indeed, in our first two experiments the maximum object speed (speed limit) for tracking targets in one visual hemifield (left or right) was not significantly affected by a requirement to track additional targets in the other hemifield. When the additional targets instead occupied the same hemifield as the original targets, the speed limit was reduced. At slow target speeds, however, adding a second target to the same hemifield had little effect. At high target speeds, the cost of adding a same-hemifield second target was approximately as large as would occur if observers could only track one of the targets. This shows that performance with a fast-moving target is very sensitive to the amount of resource allocated. In a third experiment, we investigated whether the resources for tracking can be distributed unequally between two targets. The speed limit for a given target was higher if the second target was slow rather than fast, suggesting that more resource was allocated to the faster of the two targets. This finding was statistically significant only for targets presented in the same hemifield, consistent with the theory of independent resources in the two hemifields. Some limited evidence was also found for resource sharing across hemifields, suggesting that attentional tracking resources may not be entirely hemifield-specific. Together, these experiments indicate that the largely hemisphere-specific tracking resource can be differentially allocated to faster targets.
追踪移动物体的注意过程可能在很大程度上具有半球特异性。事实上，在我们的前两个实验中，在一个视觉半视野（左或右）中追踪目标的最大物体速度（速度极限），并未受到在另一个半视野中追踪额外目标的要求的显著影响。然而，当额外目标与原始目标占据相同半视野时，速度极限会降低。不过，在目标速度较慢时，在同一半视野中添加第二个目标影响不大。在目标速度较高时，添加同一半视野的第二个目标所带来的代价，大约与观察者只能追踪其中一个目标时所产生的代价一样大。这表明，对于快速移动目标的表现，对所分配资源的数量非常敏感。在第三个实验中，我们研究了追踪资源是否可以在两个目标之间不平等分配。如果第二个目标速度慢而不是快，给定目标的速度极限会更高，这表明更多资源被分配给了两个目标中较快的那个。这一发现仅在同一半视野中呈现的目标上具有统计学意义，这与两个半视野中资源独立的理论一致。我们还发现了一些有限的证据表明跨半视野存在资源共享，这表明注意追踪资源可能并非完全具有半球特异性。总之，这些实验表明，在很大程度上具有半球特异性的追踪资源可以被差异性地分配给更快的目标。
