Perceptual learning in contrast discrimination and the (minimal) role of context
Perceptual learning in contrast discrimination and the (minimal) role of context
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DOI：
10.1167/4.3.4
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发表时间：
2004-01-01
影响因子：
1.8
通讯作者：
Levi, DM
中科院分区：
文献类型：
--
作者：
Yu, C;Klein, SA;Levi, DM
与大多数视觉任务不同，据报道，对比度辨别力不会因练习而改变（Dorais Sagi，1997; Adini，Sagi，& Tsodyks，2002），除非练习是在侧翼存在的情况下进行的（上下文使能学习，Adini et a[.，2002年）。在这里，我们表明，在几乎相同的实验条件下，在无侧翼实践实验的Adini等。（2002），实践显着提高对比度的歧视。此外，在一个单独的实验中，我们发现，没有侧翼的练习可以将对比辨别力提高到Adini等人（2002）中只有侧翼才能达到的水平，但使用侧翼的进一步练习不会进一步提高对比辨别力。这些结果让人质疑Adini等人（2002年）提出的“情境激活学习”是否不同于没有侧翼的常规对比学习。在单独的实验中，我们发现对比度学习与空间频率、方向、视网膜位置以及出乎意料的对比度有关。我们还复制了Sagi，Adini，Tsodyks和Wilkonsky（2003）最近的发现，即如果参考对比随机交错（对比漫游），则不会发生常规对比学习，并进一步证明了侧翼对对比漫游下的对比学习没有影响，这是另一个将“上下文启用学习”等同于常规对比学习的证据。学习的对比度特异性和缺乏对比度下的学习流动提供了新的证据，有利于多对比度选择性通道模型的对比度歧视，并对饱和换能器模型和乘性噪声模型。
Unlike most visual tasks, contrast discrimination has been reported to be unchanged by practice (Dorais Sagi, 1997; Adini, Sagi, & Tsodyks, 2002), unless practice is undertaken in the presence of flankers (context-enabled learning, Adini et a[., 2002). Here we show that under experimental conditions nearly identical to those in the no-flanker practice experiment of Adini et al. (2002), practice significantly improved contrast discrimination. Moreover, in a separate experiment, we found that practice without flankers can improve contrast discrimination to a level only reached with flankers in Adini et al. (2002), but further practice with flankers produces no further improvement of contrast discrimination. These results call into question whether the "context-enabled learning" proposed by Adini et al. (2002) is different from regular contrast learning without flankers. In separate experiments, we found that contrast learning is tuned to spatial frequency, orientation, retinal location, and, unexpectedly, contrast. We also replicated Sagi, Adini, Tsodyks, and Wilkonsky's (2003) more recent finding that no regular contrast learning occurs if reference contrasts are randomly interleaved (contrast roving), and further demonstrated that flankers have no effect on contrast learning under contrast roving, another piece of evidence equating "context-enabled learning" to regular contrast learning. The contrast specificity of learning and the lack of learning under contrast roving provide new evidence in favor of a multiple contrast-selective channels model of contrast discrimination, and against saturating transducer models and multiplicative noise models.