Spotting animals in natural scenes: efficiency of humans and monkeys at very low contrasts
Spotting animals in natural scenes: efficiency of humans and monkeys at very low contrasts
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DOI：
10.1007/s10071-009-0290-4
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发表时间：
2010-05-01
期刊：
影响因子：
2.7
通讯作者：
Fabre-Thorpe, Michele
中科院分区：
文献类型：
--
作者：
Mace, Marc J. -M.;Delorme, Arnaud;Fabre-Thorpe, Michele
猴子在视觉刺激（如自然场景）中对物体进行分类的能力可能依赖于一组低层次的视觉线索，而没有任何潜在的概念能力。使用一个去/不去快速动物/非动物分类任务与短暂闪烁的无色自然场景，我们表明，人类和猴子的性能是非常强大的刺激亮度和对比度的大变化。当平均亮度增加或减少25- 50%时，准确性和速度的损害很小。在最高亮度值处发现最大的损害，其中猴子主要在准确性方面受损（6%正确率下降，而人类< 1.5%），而人类主要在反应时间方面受损（中位反应时间增加20 ms，而猴子为4 ms）。对比度降低会导致图像清晰度大幅下降，但性能仍然非常稳健。即使对比度只有原始照片的12%（猴子的千分之一正确率为81%;人类的千分之一正确率为79%），受试者的得分也远高于偶然水平。准确性下降，对比度降低，但只有达到机会水平-在这两个物种-在最极端的条件下，只有3%的原始对比度。观察到反应时间逐渐增加，猴子达到72 ms，人类达到66 ms。这些结果表明，灵长类视觉系统在处理自然场景中的物体时具有显着的鲁棒性，其中亮度和对比度存在较大的随机变化。他们说明了相似性，表现受损的猴子和人类与这种刺激操纵。他们最终表明，在动物分类任务中，猴子和人类的表现在很大程度上独立于依赖于全局亮度或刺激的精细定义的线索。
The ability of monkeys to categorize objects in visual stimuli such as natural scenes might rely on sets of low-level visual cues without any underlying conceptual abilities. Using a go/no-go rapid animal/non-animal categorization task with briefly flashed achromatic natural scenes, we show that both human and monkey performance is very robust to large variations of stimulus luminance and contrast. When mean luminance was increased or decreased by 25-50%, accuracy and speed impairments were small. The largest impairment was found at the highest luminance value with monkeys being mainly impaired in accuracy (drop of 6% correct vs. < 1.5% in humans), whereas humans were mainly impaired in reaction time (20 ms increase in median reaction time vs. 4 ms in monkeys). Contrast reductions induced a large deterioration of image definition, but performance was again remarkably robust. Subjects scored well above chance level, even when the contrast was only 12% of the original photographs (a parts per thousand 81% correct in monkeys; a parts per thousand 79% correct in humans). Accuracy decreased with contrast reduction but only reached chance level -in both species- for the most extreme condition, when only 3% of the original contrast remained. A progressive reaction time increase was observed that reached 72 ms in monkeys and 66 ms in humans. These results demonstrate the remarkable robustness of the primate visual system in processing objects in natural scenes with large random variations in luminance and contrast. They illustrate the similarity with which performance is impaired in monkeys and humans with such stimulus manipulations. They finally show that in an animal categorization task, the performance of both monkeys and humans is largely independent of cues relying on global luminance or the fine definition of stimuli.