Ball Keira, Birch Yan, Lane Alison, Ellison Amanda, Schenk Thomas
Department of Psychology, Durham University, UK.
Department of Psychology, Durham University, UK.
Behav Brain Res. 2017 Jul 28;331:38-46. doi: 10.1016/j.bbr.2017.05.018. Epub 2017 May 16.
Frames of reference play a central role in perceiving an object's location and reaching to pick that object up. It is thought that the ventral stream, believed to subserve vision for perception, utilises allocentric coding, while the dorsal stream, argued to be responsible for vision for action, primarily uses an egocentric reference frame. We have previously shown that egocentric representations can survive a delay; however, it is possible that in comparison to allocentric information, egocentric information decays more rapidly. Here we directly compare the effect of delay on the availability of egocentric and allocentric representations. We used spatial priming in visual search and repeated the location of the target relative to either a landmark in the search array (allocentric condition) or the observer's body (egocentric condition). Three inter-trial intervals created minimum delays between two consecutive trials of 2, 4, or 8seconds. In both conditions, search times to primed locations were faster than search times to un-primed locations. In the egocentric condition the effects were driven by a reduction in search times when egocentric information was repeated, an effect that was observed at all three delays. In the allocentric condition while search times did not change when the allocentric information was repeated, search times to un-primed target locations became slower. We conclude that egocentric representations are not as transient as previously thought but instead this information is still available, and can influence behaviour, after lengthy periods of delay. We also discuss the possible origins of the differences between allocentric and egocentric priming effects.
参照系在感知物体位置以及伸手去拿起该物体的过程中起着核心作用。人们认为，被认为服务于感知视觉的腹侧流利用的是异我中心编码，而被认为负责动作视觉的背侧流主要使用自我中心参照系。我们之前已经表明，自我中心表征能够在延迟后留存；然而，与异我中心信息相比，自我中心信息有可能衰减得更快。在此，我们直接比较延迟对自我中心和异我中心表征可用性的影响。我们在视觉搜索中使用空间启动，并将目标位置相对于搜索阵列中的地标（异我中心条件）或观察者的身体（自我中心条件）进行重复。三个试间间隔在两个连续试验之间产生了2秒、4秒或8秒的最小延迟。在两种条件下，对启动位置的搜索时间都比对未启动位置的搜索时间要快。在自我中心条件下，当自我中心信息被重复时，搜索时间的减少推动了这种效应，在所有三种延迟情况下都观察到了这种效应。在异我中心条件下，当异我中心信息被重复时搜索时间没有变化，但对未启动目标位置的搜索时间变得更慢。我们得出结论，自我中心表征并不像之前认为的那样短暂，相反在长时间延迟后，这种信息仍然可用，并且能够影响行为。我们还讨论了异我中心和自我中心启动效应之间差异的可能来源。
