Object Perception and Representation by Echolocating Dolphins

回声定位海豚的物体知觉与表征。赫尔曼博士这项研究继续由这个实验室的调查的能力，海豚（Tursiops truncatus）感知物体的形状，通过其回声定位的感觉。 海豚是如何通过回声定位来表现它所观察到的物体的？ 它是只感知到从被声穿透的物体返回的原始回声，还是像视觉一样，直接感知到物体的形状？ 先前发表的研究使用了一种跨模态匹配样本的程序来证明海豚可以通过回声定位和视觉的感官自发地识别物体。 实验结果表明，回声定位觉能直接感知物体形状，通过回声定位获得的物体表征与通过视觉获得的物体表征是协调一致或紧密结合的。 这些结论有力地修正了以前关于海豚回声定位的观点，即假设不同物体之间的区分是基于学习将返回回声的原始声学线索联系起来（例如，振幅、高光结构或光谱组成）与所看到的事物或所接收的奖励相关联。 现在继续的调查询问海豚的表征如何忠实地保留被声穿透的物体的空间结构，以及什么机制可以支持通过回声定位构建形状感知。 其他的问题包括海豚的形状感知是否通过回声定位是不变的变化方向的对象，与变化的物质成分的对象，并与变化的对象大小。 在每个操作中，对象形状将保持不变，但对象的声音反射属性将有所不同。 跨模态匹配技术将继续使用，以及模态内技术，其中对象识别性能是在回声定位和视觉的感官内，而不是跨感官检查。 在这些研究中考虑的问题和获得的结果建立联系的问题和发现基于对象的感知和在婴儿和成人的感觉知觉，并在非人类。 这些研究还涉及人类和非人类动物记忆和表征的一般问题。

Object Perception and Representation by Echolocating DolphinsPrincipal Investigator: Louis M. Herman Ph.D.This research continues the investigation by this laboratory of the ability of the bottlenosed dolphin (Tursiops truncatus) to perceive the shape of objects through its echolocation sense. How does the dolphin represent objects it inspects through echolocation? Does it perceive only the raw echoes returning from ensonified objects or, like vision, does it directly perceive the shape of the object? The prior-published studies used a cross-modal matching-to-sample procedure to demonstrate that a dolphin could spontaneously recognize objects across the senses of echolocation and vision. The results suggested that object shape is directly perceived though the echolocation sense, and that the representations of objects obtained through echolocation are coordinated with or closely integrated with the representations obtained through vision. These conclusions strongly revise previous views of dolphin echolocation that postulated that discriminations among different objects were based on learning to associate the raw acoustic cues of returning echoes (e.g., amplitude, highlight structure, or spectral composition) with things seen or with reward received. The continuing investigations now ask how faithfully the dolphin's representations preserve the spatial structure of the object being ensonified, and what mechanisms can support the construction of a shape percept through echolocation. Other questions include whether the dolphin's perception of shape though echolocation is invariant with changes in the orientation of the object, with changes in material composition of the object, and with changes in object size. In each manipulation, object shape will remain constant, but the sound reflection properties of the object will vary. The cross-modal matching technique will continue to be used, as well as intra-modal techniques in which object recognition performance is examined within the senses of echolocation and vision rather than across the senses. The issues considered in these studies and the findings obtained establish links with issues and findings in object-based perception and in intersensory perception in infant and adult humans, and in nonhumans. The studies also make contact with general issues in memory and representation in human and nonhuman animals.