Müller Corsin A, Riemer Stefanie, Range Friederike, Huber Ludwig
Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna.
J Comp Psychol. 2014 Aug;128(3):240-50. doi: 10.1037/a0036032. Epub 2014 Mar 10.
Visible and invisible displacement tasks have been used widely for comparative studies of animals' understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and, thus, reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so because of their inability to form a mental representation of the target object, or simply because of the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object's location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species' performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past.
可见和不可见位移任务已被广泛用于动物对客体永久性理解的比较研究，越来越多的证据表明，一些物种能够解决不可见位移任务，从而达到皮亚杰客体永久性的第6阶段。相比之下，在不可见位移任务中，狗似乎依赖于关联线索，比如位移装置的位置。然而，目前尚不清楚狗以及其他在不可见位移任务中失败的物种，是因为它们无法形成目标物体的心理表征，还是仅仅因为存在一个更显著但可能会产生误导的关联线索——位移装置。我们在此表明，位移装置的使用也会损害狗在可见位移任务中的表现：当使用位移装置进行可见位移时，它们的搜索准确率显著降低，最初的42只狗中只有两只通过了假诱饵控制条件。位移装置在可见位移任务中的负面影响，可能是由于强烈的关联线索压倒了关于目标物体位置的明确信息，这类似于遮蔽效应，和/或由于目标物体被放置在位移装置内并沿着时空相同的轨迹移动而导致的物体个体化错误。我们的数据表明，对一个物种在客体永久性任务中的表现进行全面评估，应该包括使用与不可见位移中相同的位移装置进行可见位移任务，而这在过去通常没有做到。
