The perception of a complex scene requires visual mechanisms that include identifying objects and their relative placement in depth. To examine apparent depth perception in birds, we tested four pigeons with a novel multiple-sequential-choice procedure. We created 3D-rendered scene stimuli containing three objects located at different apparent depths based on a variety of pictorial cues and placed small circular target response areas on them. The pigeons were trained to sequentially choose among the multiple response areas to report the object closest in apparent depth (ordinal position; front then middle object). After the pigeons learned this sequential depth discrimination, their use of three different monocular depth cues (occlusion, relative size, height in field) was tested, and their flexibility evaluated using three novel objects. In addition to the contribution to understanding apparent depth perception in birds, the use of more flexible open-ended choice discriminations, as employed here, has considerable promise for creating informative production-like tasks in nonverbal animals.

对复杂场景的感知需要视觉机制，包括识别对象及其在深度上的相对位置。为了检查鸟类的明显深度知觉，我们用一种新颖的多顺序选择程序测试了四只鸽子。我们基于各种图像提示创建了3D渲染的场景刺激，其中包含位于不同视深度的三个对象，并在其上放置了较小的圆形目标响应区域。鸽子经过训练，可以在多个反应区域中顺序选择，以报告在表观深度上最接近的物体（原始位置；前方然后是中间物体）。在鸽子了解到这种连续的深度区分之后，测试了他们对三种不同的单眼深度线索（遮挡，相对大小，场高）的使用，并使用三个新颖的物体评估了它们的柔韧性。