University of Greenwich.
J Cogn Neurosci. 1996 Fall;8(4):371-82. doi: 10.1162/jocn.1996.8.4.371.
Current theories of visual imagery hold that the same neural processes govern both the representation of real objects and the representation of imagined (but real) objects. Here we test whether the representation of imagined (real) objects and the representation of imagined (but unreal) objects depend on the same or different neurocognitive processes. A likely clinical group for a dissociation between these two types of imagination are children with autism, since they show deficits in imaginative play, impoverished imagination is part of their diagnosis, but they can search for hidden objects. The present study explored imagination in autism using experimental methods. Experiment 1 investigated if children with autism could introduce changes to their representations of people and houses, using Karmiloff-Smith's (1989) technique of asking children to draw "impossible" people or houses. Results showed that children with autism were significantly worse than matched controls in their ability to introduce "unreal" changes to their representations of people and houses. Instead, they tended to draw real people or objects. Experiment 2 investigated whether the performance in Experiment 1 by children with autism was due to an inability to disengage from "real world" representations, as executive dysfunction theorists would argue. To do this, the experimenter instructed them on what to draw and how to draw it. Results showed that even when executive control passed to the experimenter in this way, the children with autism were still significantly impaired in their ability to draw imaginary but unreal things relative to the matched controls. Experiment 3 investigated whether the results from Experiments 1 and 2 arose because of a generativity deficit in autism, which might be the executive dysfunction theorists' alternative account. To test this, the same subjects were given a test of Verbal Fluency and a test of imagining multiple functions of a brick. Results showed that the children with autism were no worse than clinical controls in their ability to generate ideas about real objects, suggesting that a global generativity deficit cannot explain the previous findings. Rather, these results point to a specific impairment in the ability to imagine unreal objects. This is discussed in terms of its possible neural dissociability from other kinds of imagery, and in terms of its possible relationship to theory of mind.
当前的视觉意象理论认为，相同的神经过程既支配着真实物体的表象，也支配着想象（但真实）物体的表象。在这里，我们测试想象（真实）物体的表象和想象（但不真实）物体的表象是否依赖于相同或不同的神经认知过程。想象（真实）物体和想象（不真实）物体之间的这种分离在自闭症儿童中可能是一个明显的临床群体，因为他们在想象游戏中表现出缺陷，想象贫乏是他们诊断的一部分，但他们可以寻找隐藏的物体。本研究使用实验方法探索了自闭症中的想象。实验 1 调查了自闭症儿童是否能够使用 Karmiloff-Smith（1989）的技术改变他们对人和房子的表象，要求他们画“不可能”的人和房子。结果表明，自闭症儿童在改变他们对人和房子的表象的“不真实”方面的能力明显不如匹配对照组。相反，他们倾向于画真实的人和物体。实验 2 调查了自闭症儿童在实验 1 中的表现是否是由于执行功能理论家所说的无法从“现实世界”的表象中脱离出来。为此，实验者指导他们画什么和如何画。结果表明，即使以这种方式将执行控制交给实验者，自闭症儿童在想象但不真实的事物方面的能力仍然明显受损，与匹配对照组相比。实验 3 调查了实验 1 和实验 2 的结果是否是由于自闭症中的生成性缺陷，这可能是执行功能理论家的另一种解释。为了测试这一点，相同的受试者接受了言语流畅性测试和一块砖的多种功能想象测试。结果表明，自闭症儿童在生成关于真实物体的想法的能力上并不比临床对照组差，这表明普遍的生成性缺陷不能解释之前的发现。相反，这些结果表明，他们在想象不真实物体的能力上存在特定的障碍。这是从与其他类型的意象的可能神经可分离性以及与心理理论的可能关系的角度来讨论的。
