Ellemberg Dave, Hansen Bruce C, Johnson Aaron
Université de Montréal, Department of Kinesiology, Montréal, Québec, Canada.
Vision Res. 2012 Aug 15;67:1-7. doi: 10.1016/j.visres.2012.06.018. Epub 2012 Jul 2.
The adult visual system is optimally tuned to process the spatial properties of natural scenes, which is demonstrated by sensitivity to changes in the 1/f(α) amplitude spectrum. It is also well documented that different aspects of spatial vision, including those likely responsible for the perception of natural scenes (e.g., spatial frequency discrimination), do not become mature until late childhood. This led us to hypothesise that the developing visual system is not optimally tuned to process the spatial properties of real-world scenes. The present study investigated how sensitivity to the statistical properties of natural images changes during development. Thresholds for discriminating a change in the slope of the amplitude spectrum of a natural scene with a reference α of 0.7, 1.0, or 1.3 where measured in children aged 6, 8, and 10 years (n=16 per age) and in adults (mean age=23). Consistent with previous studies, adults were least sensitive for the shallowest α (i.e., 0.7) and most sensitive for the steepest α (i.e., 1.3). Six- and 8-year-olds had significantly higher discrimination thresholds compared to the 10-year-olds and adults for α's of 1.0 and 1.3, and 10-year-olds did not differ significantly from adults for any of the α's tested. These data suggest that sensitivity to detecting a change in the spatial characteristics of natural scenes during childhood may not be optimally tuned to the statistics of natural images until about 10 years of age. Rather, is seems that perception of natural images could be limited by the known immaturities in spatial vision (Ellemberg, Lepore, & Turgeon, 2010). The question remains as to whether the adult's exquisite sensitivity to the spatial properties of the natural world is experience driven or whether it is part of our genetic programming that only fully expresses itself in late childhood.
成人视觉系统经过优化调整，能够处理自然场景的空间特性，这一点通过对1/f(α)振幅谱变化的敏感性得到了证明。同样有充分文献记载的是，空间视觉的不同方面，包括那些可能负责自然场景感知的方面（例如空间频率辨别），直到童年晚期才会成熟。这使我们推测，发育中的视觉系统并未经过优化调整以处理现实世界场景的空间特性。本研究调查了在发育过程中对自然图像统计特性的敏感性是如何变化的。在6岁、8岁和10岁的儿童（每个年龄段n = 16）以及成年人（平均年龄 = 23岁）中测量了辨别自然场景振幅谱斜率变化的阈值，参考α值分别为0.7、1.0或1.3。与先前的研究一致，成年人对最浅的α（即0.7）最不敏感，对最陡的α（即1.3）最敏感。对于α值为1.0和1.3的情况，6岁和8岁儿童的辨别阈值显著高于10岁儿童和成年人，而对于所测试的任何α值，10岁儿童与成年人之间没有显著差异。这些数据表明，在童年时期，对检测自然场景空间特征变化的敏感性可能直到大约10岁时才根据自然图像的统计特性进行优化调整。相反，似乎自然图像的感知可能受到空间视觉中已知不成熟因素的限制（埃伦伯格、勒波雷和图尔热翁，2010年）。问题仍然存在，即成年人对自然世界空间特性的敏锐敏感性是由经验驱动的，还是它是我们基因编程的一部分，只是在童年晚期才完全表现出来。
