Mechanisms of active vison in barn owls: Stable perception through atomic head movements

为了生存，大多数动物必须获得和衡量与物理世界相关的感官信息，以指导行为。信息可以被动地收集，分析传入的感官信息，也可以通过动物的行为主动收集。这项建议调查的视觉大小歧视谷仓猫头鹰作为一个特殊的情况。该项目分为三个工作包。第一个工作包的目标是描述和确定仓鸮区分不同大小物体的能力。第二个工作包介绍了不同的距离作为一个案例的推广和调查的现象，在谷仓猫头鹰的大小恒常性。第三个工作包将解决仓鸮如何以积极的方式使用运动视差的问题，不仅可以推断距离，还可以推断物体的大小。后一种方法也是为了提高我们对仓鸮头部明显的侧向运动的功能性理解。人类受试者的实验将平行进行。它们将产生有趣的独立数据，表征人类视觉系统的各个方面。 从这项研究中，视觉缩放因子应该可以在物种之间进行比较，以促进我们从进化的角度对视觉行为的理解。我们认为，这项研究可能最终导致更好地理解视觉取向，并可能是有价值的应用目的。

In order to survive most animals have to acquire and scale sensory information in reference to the physical world to guide behavior. Information may be either collected passively, analyzing incoming sensory information, or actively, by the actions of the animals. This proposal investigates visual size discrimination in the barn owl as a special case. The project is divided into three work packages. The goal in the first work package is to describe and determine how well the barn owl is capable to discriminate objects of different sizes. The second work package introduces different distances as a case of generalization and investigates the phenomenon of size constancy in barn owls. The third work package will tackle the question how the barn owl uses motion parallax in an active fashion, not only to infer distance, but also the size of an object. The latter approach is also designed to improve our functional understanding of the conspicuous side-to-side head movements observed in barn owls. Experiments with human subjects will be carried out in parallel. They will yield interesting independent data characterizing aspects of the human visual system. From this studies a visual scaling factor should result that might be compared between species to advance our understanding of visual behaviors from an evolutionary perspective. We think that this research may eventually lead to a better understanding of visual orientation and may be valuable for application purposes.