Kohler Axel, Haddad Leila, Singer Wolf, Muckli Lars
Department of Neurophysiology, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
Vision Res. 2008 Mar;48(8):1096-106. doi: 10.1016/j.visres.2007.11.020. Epub 2008 Feb 14.
Apparent motion is an illusory perception of movement that can be induced by alternating presentations of static objects. Already in Wertheimer's early investigation of the phenomenon [Wertheimer, M. (1912). Experimentelle Studien über das Sehen von Bewegung. Zeitschrift fur Psychologie, 61, 161-265], he mentions that voluntary attention can influence the way in which an ambiguous apparent motion display is perceived. But until now, few studies have investigated how strong the modulation of apparent motion through attention can be under different stimulus and task conditions. We used bistable motion quartets of two different sizes, where the perception of vertical and horizontal motion is equally likely. Eleven observers participated in two experiments. In Experiment 1, participants were instructed to either (a) hold the current movement direction as long as possible, (b) passively view the stimulus, or (c) switch the movement directions as quickly as possible. With the respective instructions, observers could almost double phase durations in (a) and more than halve durations in (c) relative to the passive condition. This modulation effect was stronger for the large quartets. In Experiment 2, observers' attention was diverted from the stimulus by a detection task at fixation while they still had to report their conscious perception. This manipulation prolonged dominance durations for up to 100%. The experiments reveal a high susceptibility of ambiguous apparent motion to attentional modulation. We discuss how feature- and space-based attention mechanisms might contribute to those effects.
似动是一种对运动的错觉感知，可由静态物体的交替呈现诱发。早在韦特海默对该现象的早期研究中[韦特海默，M.（1912年）。关于运动视觉的实验研究。《心理学杂志》，61卷，第161 - 265页]，他就提到，随意注意会影响对模糊似动显示的感知方式。但到目前为止，很少有研究探讨在不同刺激和任务条件下，注意对似动的调节作用能有多强。我们使用了两种不同大小的双稳态运动四重奏，其中垂直和水平运动的感知可能性相同。11名观察者参与了两项实验。在实验1中，参与者被指示要么（a）尽可能长时间保持当前运动方向，（b）被动观看刺激，要么（c）尽快切换运动方向。按照各自的指示，相对于被动条件，观察者在（a）中可使相位持续时间几乎翻倍，在（c）中可使其持续时间减半以上。这种调节效应在大四重奏中更强。在实验2中，观察者在注视点处通过一个检测任务将注意力从刺激上转移开，同时他们仍需报告自己的有意识感知。这种操作使优势持续时间延长了高达100%。这些实验揭示了模糊似动对注意调节的高度敏感性。我们讨论了基于特征和空间的注意机制可能如何促成这些效应。
