Simultaneous modeling of visual saliency and value computation improves predictions of economic choice
Simultaneous modeling of visual saliency and value computation improves predictions of economic choice
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DOI：
10.1073/pnas.1304429110
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发表时间：
2013-10-01
影响因子：
11.1
通讯作者：
Koch, Christof
中科院分区：
文献类型：
--
作者：
Towal, R. Blythe;Mormann, Milica;Koch, Christof
我们所做的许多决定都需要快速地从视觉上识别和评估众多备选方案。它们通常在奖励或价值以及低级视觉特性（如显著性）上有所不同。显著性和价值都会影响最终的决策。特别是，显著性影响注视的位置和持续时间，这是预测选择的因素。然而，尚不清楚显著性如何传播到最终决定。此外，显著性和价值的相对影响尚不清楚。在这里，我们用一个综合模型来解决这些问题，这个模型结合了关于在哪里和什么时候看的感性决策过程和关于选择什么的经济决策过程。感知决策过程建模为每个备选方案的漂移-扩散模型（DDM）过程。使用来自多选项强迫选择任务的心理物理数据，在该任务中，受试者必须通过眼球运动从拥挤的展示中选择一种食物，我们测试了四个模型，其中每个DDM过程由(i)显著性或（ii）单独的价值或（iii）加法或（iv）两者的乘法组合驱动。我们发现，包括显著性和价值权重在三分之一到三分之二的比例（显著性对价值）的模型明显优于仅基于数量的模型。这些注视模式调节了经济决策过程，也被描述为价值驱动的DDM过程。我们的组合模型定量地解释了固定模式和选择，其精确度与以前的模型相似或更高，这表明视觉显著性的影响比价值更小，但更重要，并且显著性通过调节经济决策的感知决策间接影响选择。
Many decisions we make require visually identifying and evaluating numerous alternatives quickly. These usually vary in reward, or value, and in low-level visual properties, such as saliency. Both saliency and value influence the final decision. In particular, saliency affects fixation locations and durations, which are predictive of choices. However, it is unknown how saliency propagates to the final decision. Moreover, the relative influence of saliency and value is unclear. Here we address these questions with an integrated model that combines a perceptual decision process about where and when to look with an economic decision process about what to choose. The perceptual decision process is modeled as a drift-diffusion model (DDM) process for each alternative. Using psychophysical data from a multiple-alternative, forced-choice task, in which subjects have to pick one food item from a crowded display via eye movements, we test four models where each DDM process is driven by (i) saliency or (ii) value alone or (iii) an additive or (iv) a multiplicative combination of both. We find that models including both saliency and value weighted in a one-third to two-thirds ratio (saliency-to-value) significantly outperform models based on either quantity alone. These eye fixation patterns modulate an economic decision process, also described as a DDM process driven by value. Our combined model quantitatively explains fixation patterns and choices with similar or better accuracy than previous models, suggesting that visual saliency has a smaller, but significant, influence than value and that saliency affects choices indirectly through perceptual decisions that modulate economic decisions.