Yaman Sevgi, von Fersen Lorenzo, Dehnhardt Guido, Güntürkün Onur
Marineland Mallorca, Costa d'En Blanes, 07184 Calvia, Mallorca, Spain.
Behav Brain Res. 2003 Jun 16;142(1-2):109-14. doi: 10.1016/s0166-4328(02)00385-6.
A previous behavioural study with a single bottlenose dolphin had reported a right eye superiority in visual discrimination tasks, indicating a left hemisphere dominance for visual object processing. The presence of a functional asymmetry demonstrated with one individual shows that this function can be lateralized in this single animal, but cannot reveal if this represents a population asymmetry. Therefore, we conducted a series of visual discrimination experiments with three individuals of Tursiops truncatus under monocular conditions. The tested animals had to distinguish between simultaneously presented stimulus pairs of different patterns, whereby one stimulus was always defined to be correct. Additionally, the animals were observed for their free eye use during training and introduction of new items. The present data set revealed a right eye advantage (left hemisphere dominance) for all tested animals and a predominance of right eye use during daily activities. These results make it possible that bottlenose dolphins are lateralized for visual pattern discrimination at the level of a population asymmetry. Against the background of similar data in other vertebrates, a left hemisphere dominance for pattern discrimination points to the possibility that dolphins exploit local visual details instead of global configurational features to recognize and memorize visual stimuli.
先前一项针对单只宽吻海豚的行为研究报告称，在视觉辨别任务中该海豚右眼占优，这表明其左半球在视觉物体处理方面占主导地位。仅在一只个体身上表现出的功能不对称现象表明，这种功能在这只个体中可以发生偏侧化，但无法揭示这是否代表了群体的不对称性。因此，我们对三头宽吻海豚个体在单眼条件下进行了一系列视觉辨别实验。受试动物必须区分同时呈现的不同图案的刺激对，其中一种刺激总是被定义为正确的。此外，在训练和引入新物品的过程中，观察了动物自由使用眼睛的情况。目前的数据集显示，所有受试动物都存在右眼优势（左半球占主导），且在日常活动中右眼使用更为频繁。这些结果表明，宽吻海豚在群体不对称水平上存在视觉图案辨别偏侧化现象。基于其他脊椎动物的类似数据，图案辨别方面的左半球占主导表明，海豚可能利用局部视觉细节而非全局构型特征来识别和记忆视觉刺激。
