Perception and Action Lab, Department of Psychology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
Exp Brain Res. 2021 Jul;239(7):2207-2220. doi: 10.1007/s00221-021-06076-x. Epub 2021 May 19.
The two-visual stream hypothesis posits that the dorsal stream is less susceptible than the ventral stream to the effects of illusions and visual priming. While previous studies have separately examined these perceptual manipulations, the present study combined the effects of a visual illusion and priming to examine the possibility of dorsally guided actions being susceptible to the perceptual stimuli due to interactions between the two streams. Thirty-four participants were primed with a 'long' or 'short' version of the Sander Parallelogram illusion and were asked to either reach out and grasp or manually estimate the length of a rod placed on a version of the illusion that was on some trials the same as the prime (congruent) and on other trials was the inverse (incongruent). Due to the context-focused nature of ventral processing, we predicted that estimations would be more susceptible to the effects of the illusion and priming than grasps. Results showed that while participants' manual estimations were susceptible to both priming and the illusion, the grasps were only affected by the illusion, not by priming. The influence of the illusion on grip aperture was greater during manual estimations than it was during grasping. These findings support the notion that the functionally distinct dorsal and ventral streams interact under the current experimental paradigm. Outcomes of the study help better understand the nature of stimuli that promote interactions between the dorsal and ventral streams.
双视觉流假说认为，与腹侧流相比，背侧流不易受到错觉和视觉启动的影响。虽然之前的研究分别检查了这些感知操作，但本研究结合了视觉错觉和启动的影响，以检查由于两个流之间的相互作用，背向引导的动作是否容易受到感知刺激的影响。34 名参与者接受了 Sander 平行四边形错觉的“长”或“短”版本的启动，并被要求伸手抓住或手动估计放在错觉上的一根棒的长度，在一些试验中与启动（一致）相同，而在其他试验中则相反（不一致）。由于腹侧处理的上下文聚焦性质，我们预测估计比抓握更容易受到错觉和启动的影响。结果表明，虽然参与者的手动估计受到启动和错觉的影响，但抓握仅受错觉影响，不受启动影响。在手动估计期间，错觉对握力开口的影响大于在抓握期间的影响。这些发现支持了这样一种观点，即功能上不同的背侧和腹侧流在当前实验范式下相互作用。该研究的结果有助于更好地理解促进背侧和腹侧流之间相互作用的刺激的性质。
