Kristjánsson Arni
Vision Sciences Laboratory, Harvard University, USA.
Perception. 2006;35(7):865-81. doi: 10.1068/p5526.
Recent results have suggested that the operational units of visual short-term memory (VSTM) are whole objects, rather than features or the total amount of information to be remembered. Here, for the first time, the influence of surface assignment on object formation for VSTM was investigated. The observers had to memorize the features of four briefly presented (300 ms) two-part objects, followed by a mask and a cue indicating which object to report on. The experiments contrasted whether there were any apparent depth differences between the two parts of each object, and whether observers had to report on only one or both features of the post-cued target object. Depth differences induced with stereoscopic disparity, and with a pictorial depth cue (simple interposition of object features), interfered strongly with performance when both features of an object needed to be memorized, but aided performance when only a single feature needed to be remembered. Furthermore, there was considerable within-feature interference consistent with some previous findings, but contradicting others. The potential implications for conceptions of VSTM are discussed in the light of two hypothesized stages: an early feature-based stage, as well as a higher-level object-based stage where the depth manipulations exert their effects. The results argue for a strong modulatory influence of surface assignment on object formation for a VSTM task.
近期的研究结果表明，视觉短期记忆（VSTM）的操作单元是完整的物体，而非特征或要记忆的信息总量。在此，首次对表面分配对VSTM物体形成的影响进行了研究。观察者必须记住四个短暂呈现（300毫秒）的两部分物体的特征，随后是一个掩蔽物和一个提示，指示要报告哪个物体。实验对比了每个物体的两部分之间是否存在明显的深度差异，以及观察者是否只需报告提示后目标物体的一个特征还是两个特征。由立体视差和图形深度线索（物体特征的简单遮挡）引起的深度差异，在需要记住物体的两个特征时会强烈干扰表现，但在只需记住单个特征时则有助于表现。此外，存在相当程度的特征内干扰，这与之前的一些发现一致，但与其他发现相矛盾。根据两个假设阶段讨论了对VSTM概念的潜在影响：一个早期的基于特征的阶段，以及一个更高层次的基于物体的阶段，深度操作在该阶段发挥作用。结果表明表面分配对VSTM任务的物体形成具有强烈的调节作用。
