VISION SCIENCE 视觉科学
Photons to Phenomenology 从光子到现象学
Stephen E. Palmer 斯蒂芬-E-帕尔默
Figure 2.1.9 Texture gradients. When a surface consisting of many similar objects is slanted in depth, they form an image texture whose elements gradually gets smaller, denser, and more foreshortened as the surface recedes in distance.
图 2.1.9 纹理渐变。当一个由许多相似物体组成的表面在深度上倾斜时,就会形成一种图像纹理,随着表面距离的拉近,纹理的元素会逐渐变小、变密和变得更加模糊。
Gibson’s theory of ecological optics is also important because it emphasized perceiving as the active exploration of the environment and the informational consequences of this fact. When the observer moves about in the world, the spatial pattern of stimulation on the retina constantly changes over time. Gibson stressed the richness of this optic flow on the retina in understanding perception and invented the concept of the dynamic AOA (see Section 1.2.1) to refer to it. Much of the earlier work on perception was based on studying subjects who sat with their heads immobilized while viewing stationary stimuli under highly restricted and artificial conditions. But Gibson and his followers argued forcefully that perceptual systems evolved in organisms on the move: seeking food, water, mates, and shelter. The theory of ecological optics therefore tries to specify what information about the environment is available to the eyes of a moving observer.
吉布森的生态光学理论也很重要,因为它强调感知是对环境的主动探索,以及这一事实的信息后果。当观察者在世界上移动时,视网膜上的空间刺激模式会随着时间的推移而不断变化。吉布森强调视网膜上的这种视流在理解知觉方面的丰富性,并发明了动态 AOA 概念(见第 1.2.1 节)来指代它。早期关于知觉的研究大多基于研究对象在高度受限的人工条件下,头部固定不动地坐着观看静止的刺激物。但吉布森和他的追随者们有力地指出,感知系统是在生物的移动过程中进化而来的:寻找食物、水、配偶和住所。因此,生态光学理论试图明确移动观察者的眼睛可以获得哪些环境信息。
One of Gibson’s most important and original insights in studying the information available in the dynamic AOA is that the same optical information that specifies the nature of the environment also specifies the trajectory of the observer through it. The sequence of views shown in Figure 2.1.10, for example, not only indicates the presence of a doorway leading to a different room, but also specifies the observer’s direction of approach. Perception of the environment and of the moving station point are thus codetermined
吉布森在研究动态视角中的信息时,最重要和最新颖的见解之一是,说明环境性质的光学信息也说明了观察者穿过环境的轨迹。例如,图 2.1.10 所示的视图序列不仅表明存在一个通往不同房间的门洞,而且还指明了观察者的前进方向。因此,对环境和移动站点的感知是由以下因素共同决定的
by the nature of the optical information reaching the eye.
由到达眼睛的光学信息的性质决定。
Gibson believed that sufficient information was available in retinal stimulation to allow an actively exploring organism to perceive the environment unambiguously. He called the process by which the brain accomplished this feat information pickup. Although he was less concerned with the biological mechanisms of perception than he was with their informational support in the stimulus, he suggested a resonance metaphor for how this process of information pickup might occur. Gibson likened the brain to a system of tuning forks and suggested that whatever the brain might be doing in detail, it was analogous to a process of mechanical resonance (Gibson, 1966, 1979). Information in the stimulus simply causes the appropriate neural structures in the brain to fire, much as mechanical vibration of a specific frequency in the air causes a tuning fork of the same characteristic frequency to vibrate. Unfortunately, Gibson never developed this analogy much further. It is an interesting idea, not unrelated to Köhler’s idea of a physical Gestalt, but needs much more elaboration to be testable in any meaningful way.
吉布森认为,视网膜刺激可以提供足够的信息,让积极探索的生物体明确地感知环境。他把大脑完成这一壮举的过程称为信息拾取。虽然他对感知的生物机制并不那么关注,但他还是提出了一个共振隐喻,来说明这一信息拾取过程是如何发生的。吉布森将大脑比作一个音叉系统,并认为无论大脑在做什么细节工作,都类似于一个机械共振过程(吉布森,1966 年,1979 年)。刺激中的信息只会引起大脑中相应的神经结构发生反应,就像空气中特定频率的机械振动会引起具有相同特征频率的音叉振动一样。遗憾的是,吉布森从未对这一类比作进一步的发展。这是一个有趣的想法,与科勒关于物理格式塔的想法不无关系,但需要更多的阐述才能进行有意义的测试。
Direct Perception. By far the most controversial aspect of Gibson’s theory was his proposal of direct perception: the idea that visual perception of the environment is fully specified by the optical information available at the retina of a moving, actively exploring organism without any mediating processes or internal representations. (The degree of disagreement over this idea is well represented by Ullman’s (1980) critique “Against Direct Perception” and the 27 commentaries that follow it.) In trying to understand Gibson’s idea of direct perception, it is helpful to realize that he was reacting against earlier proposals that perception is possible only by making “unconscious inferences” that go beyond the information strictly given in the sensory stimulation (see Section 2.1.4 on constructivism). He categorically rejected this influential account of perception, claiming instead that inferences are not needed if one takes into account the many sources of optical information that were not considered in the traditional analysis of static retinal images, particularly those available in optic flow as the organism explores the environment.
直接感知。迄今为止,吉布森理论中最具争议的方面是他提出的直接知觉:即对环境的视觉感知完全由运动的、积极探索的有机体视网膜上的光学信息所决定,而不需要任何中介过程或内部表征。(乌尔曼(Ullman,1980 年)的评论文章《反对直接感知》及其后的 27 篇评论充分体现了对这一观点的分歧程度)。在试图理解吉布森的直接知觉观点时,我们不妨认识到,吉布森是在对早先提出的知觉只能通过 "无意识推断 "才能实现的观点做出反应,而 "无意识推断 "严格来说超出了感官刺激所提供的信息(见第 2.1.4 节关于建构主义的内容)。他断然拒绝了这种对知觉有影响的说法,转而声称,如果考虑到传统的静态视网膜图像分析中没有考虑到的许多光学信息来源,尤其是生物体探索环境时在视流中获得的信息,就不需要推论了。