Department of Neurofarba, University of Florence, Florence, Italy.
Department of Education, Roma Tre University, Florence, Italy.
PLoS One. 2021 Oct 11;16(10):e0258490. doi: 10.1371/journal.pone.0258490. eCollection 2021.
Motion can be perceived in static images, such as photos and figurative paintings, representing realistic subjects in motion, with or without directional information (e.g., motion blur or speed lines). Motion impression can be achieved even in non-realistic static images such as motion illusions and abstract paintings. It has been shown that visual motion processing affects the diameter of the pupil, responding differently to real, illusory, and implied motion in photographs (IM). It has been suggested that these different effects might be due to top-down modulations from different cortical areas underlying their processing. It is worthwhile to investigate pupillary response to figurative paintings, since they require an even higher level of interpretation than photos representing the same kind of subjects, given the complexity of cognitive processes involved in the aesthetic experience. Also, pupil responses to abstract paintings allows to study the effect of IM perception in representations devoid of real-life motion cues. We measured pupil responses to IM in figurative and abstract artworks depicting static and dynamic scenes, as rated by a large group of individuals not participating in the following experiment. Since the pupillary response is modulated by the subjective image interpretation, a motion rating test has been used to correct individual pupil data according to whether participants actually perceived the presence of motion in the paintings. Pupil responses to movies showing figurative and abstract subjects, and to motion illusions were also measured, to compare real and illusory motion with painted IM. Movies, both figurative and abstract, elicit the largest pupillary dilation of all static stimuli, whereas motion illusions cause the smallest pupil size, as previously shown. Interestingly, pupil responses to IM depend on the paintings' style. Figurative paintings depicting moving subjects cause more dilation than those representing static figures, and pupil size increases with the strength of IM, as already found with realistic photos. The opposite effect is obtained with abstract artworks. Abstract paintings depicting motion produce less dilation than those depicting stillness. In any case, these results reflect the individual subjective perception of dynamism, as the very same paintings can induce opposite responses in observer which interpreted it as static or dynamic. Overall, our data show that pupil size depends on high-level interpretation of motion in paintings, even when they do not represent real-world scenes. Our findings further suggest that the pupil is modulated by multiple top-down cortical mechanisms, involving the processing of motion, attention, memory, imagination, and other cognitive functions necessary for enjoying a complete aesthetic experience.
运动可以在静态图像中被感知,例如照片和具象绘画,它们代表了运动中的现实主题,具有或不具有方向信息(例如,运动模糊或速度线)。即使是在非现实的静态图像中,如运动错觉和抽象绘画,也可以产生运动印象。已经表明,视觉运动处理会影响瞳孔的直径,对照片中的真实、虚幻和隐含运动(IM)有不同的反应。有人认为,这些不同的影响可能是由于不同皮质区域的自上而下的调制,这些皮质区域是其处理的基础。研究具象绘画的瞳孔反应是值得的,因为与代表相同主题的照片相比,它们需要更高水平的解释,因为涉及到审美体验的认知过程的复杂性。此外,对抽象绘画的瞳孔反应可以研究在没有现实生活运动线索的表象中隐含运动感知的影响。我们测量了对静态和动态场景的具象和抽象艺术作品中 IM 的瞳孔反应,这些作品是由一大群没有参与以下实验的个体进行评分的。由于瞳孔反应受到主观图像解释的调制,因此使用运动评分测试根据参与者实际上是否感知到绘画中的运动存在来校正个体的瞳孔数据。还测量了显示具象和抽象主题的电影以及运动错觉的瞳孔反应,以比较真实和虚幻运动与绘画 IM。如前所示,与所有静态刺激相比,具象和抽象电影都会引起最大的瞳孔扩张,而运动错觉会导致最小的瞳孔尺寸。有趣的是,IM 的瞳孔反应取决于绘画的风格。具象绘画描绘运动的主体会比描绘静态人物的主体引起更大的扩张,并且瞳孔大小会随着 IM 的强度而增加,就像真实照片一样。而对于抽象艺术则会产生相反的效果。抽象绘画描绘运动的作品比描绘静止的作品引起的扩张小。在任何情况下,这些结果都反映了个体对动力的主观感知,因为同一幅画可能会引起观察者的相反反应,观察者将其解释为静态或动态。总的来说,我们的数据表明,即使绘画不代表现实世界的场景,瞳孔大小也取决于对绘画中运动的高级解释。我们的研究结果进一步表明,瞳孔受到涉及运动、注意力、记忆、想象力和其他认知功能的多个自上而下的皮质机制的调制,这些功能对于享受完整的审美体验是必要的。