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视觉加工不仅仅取决于刺激的基本属性，还与很多高级的认知因素有关。奖赏是一种高级认知因素，主要通过两种方式影响视知觉。一方面，根据表现给予奖赏能够诱发动机调控视觉加工;另一方面，与奖赏联结的视觉刺激能够自发获得知觉优势。

首先，奖赏可以作为积极诱因激发动机，调动认知资源，促进相关任务的表现，但它对无关任务的影响尚不清楚。研究一则同时考察了奖赏如何影响相关和无关任务的视知觉加工。我们采用两个经典的视知觉任务，对其中一个任务根据成绩给予金钱奖励(相关任务)，另一个不给(无关任务)。通过四个实验我们发现:无论两个任务是随机在试次间、组间穿插，还是先后进行，奖赏都促进了相关任务的表现，而损害了无关任务的成绩。这种依赖表现的金钱奖赏也许提高了被试对相关任务的动机，但破坏了对无关任务的动机。本研究首次揭示了奖赏对视知觉加工的消极作用，提示我们要谨慎使用奖赏手段。

此外，通过奖赏与视觉刺激的联结学习，奖赏相关刺激能够自动捕获注意，但目前尚无研究探讨这种基于奖赏的注意对对比度知觉的影响。研究二则具体考察了奖赏联结的注意线索如何调控附近刺激的对比度知觉。我们首先通过训练将奖赏与颜色建立联结，之后撤去奖赏、采用注意指向范式进行测试，发现与高奖赏联结的圆环可以吸引注意，并且高奖赏线索同侧光栅的对比度看起来更高。本研究验证了奖赏可以通过注意调控对比度主观知觉，这个作用可能发生在视觉加工的早期阶段。

综上所述，本文通过两个研究探讨了奖赏对视知觉加工的复杂影响，揭示了大脑初级和高级加工的相互作用以及奖赏网络、注意系统和视觉皮层动态交互的工作模式。

Visual processing is not only determined by basic features of stimuli but also by high-level cognitive factors. Reward as a kind of high-level cognitive factor can influence visual perception via two ways. On the one hand, giving reward according to one's performance can induce motivation and modulate visual processing. On the other hand, reward-associated visual stimuli can automatically gain privileged access to perception.

Firstly, reward can induce strong motivation，mobilize cognitive resources and promote the performance of relevant visual tasks as a positive incentive， but it's influence on irrelevant tasks is unclear. Study 1 investigated how reward changes the visual perception of both relevant task and irrelevant task. We used two classical visual perception tasks, with one being rewarded (reward-relevant task) and the other not being rewarded (reward-irrelevant task). In all the four experiments, we found that regardless of whether the two tasks were randomly intermixed trial by trial or presented block by block or session by session, reward improved the performance on the relevant task but impaired the performance on the irrelevant task. This performance-dependent money reward may enhance the motivation of relevant task undermine the motivation of irrelevant task. This study was the first to reveal the negative effect of reward on visual perception and it reminded us to use reward cautiously.

Besides, after associative learning, reward-associated stimuli can automatically capture attention. Nevertheless，there are no researches investigating the effects of value-associated attention on contrast perception. Study 2 specifically focused on how reward-associated attention alters the perceived contrast of visual stimuli.

After associating value with color of circles in a training session, we withdrew reward and conducted a test using spatial cuing paradigm. We found that high-reward-associated circles attracted attention and the contrast of ipsilateral gabor patches looked higher. The study provided evidence that reward potentiated the effects of attention on contrast appearance and this may happen at early stages of visual processing.

In conclusion, the two researches in this paper investigated the complex influence of monetary reward on visual perception. They indicated the interaction of low-level and high-level processing in the brain and the dynamic interplay between reward network, attention system and visual cortex.