A defining feature of children's cognition is the especially slow development of their attention. Despite a rich behavioral literature characterizing the development of attention, little is known about how developing attentional abilities modulate neural representations in children. This information is critical to understanding how attentional development shapes the way children process information. One possibility is that attention might be less likely to shape neural representations in children as compared with adults. In particular, representations of attended items may be less likely to be enhanced relative to unattended items. To investigate this possibility, we measured brain activity using fMRI while children (seven to nine years; male and female) and adults (21–31 years; male and female) performed a one-back task in which they were directed to attend to either motion direction or an object in a display where both were present. We used multivoxel pattern analysis to compare decoding accuracy of attended and unattended information. Consistent with attentional enhancement, we found higher decoding accuracy for task-relevant information (i.e., objects in the object-attended condition) than for task-irrelevant information (i.e., motion in the object-attended condition) in adults' visual cortices. However, in children's visual cortices, both task-relevant and task-irrelevant information were decoded equally well. What is more, whole-brain analysis showed that the children represented task-irrelevant information more than adults in multiple regions across the brain, including the prefrontal cortex. These findings show that (1) attention does not modulate neural representations in the child visual cortex, and (2) developing brains can, and do, represent more information than mature brains.

SIGNIFICANCE STATEMENT Children have been shown to struggle with maintaining their attention to specific information, and at the same time, can show better learning of "distractors." While these are critical properties of childhood, their underlying neural mechanisms are unknown. To fill in this critical knowledge gap, we explored how attention shapes what is represented in children's and adults' brains using fMRI while both were asked to focus on just one of two things (objects and motion). We found that unlike adults, who prioritize the information they were asked to focus on, children represent both what they were asked to prioritize and what they were asked to ignore. This shows that attention has a fundamentally different impact on children's neural representations.

儿童认知的一个显着特征是他们的注意力发展特别缓慢。尽管有丰富的行为文献描述了注意力的发展，但人们对注意力能力的发展如何调节儿童的神经表征知之甚少。这些信息对于理解注意力发展如何影响儿童处理信息的方式至关重要。一种可能性是，与成人相比，注意力不太可能塑造儿童的神经表征。特别地，相对于无人看管的项目，有人看管的项目的表示可能不太可能被增强。为了研究这种可能性，我们使用功能磁共振成像测量了儿童（7 至 9 岁；男性和女性）和成人（21-31 岁；男性和女性）执行一项单背任务时的大脑活动，其中他们被指示注意运动方向或显示器中两者都存在的对象。我们使用多体素模式分析来比较有人值守和无人值守信息的解码准确性。与注意力增强一致，我们发现成人视觉皮层中与任务相关的信息（即，对象关注条件下的对象）的解码精度高于任务无关信息（即，对象关注条件下的运动）的解码精度。然而，在儿童的视觉皮层中，与任务相关和与任务无关的信息的解码效果一样好。更重要的是，全脑分析表明，儿童在大脑的多个区域（包括前额叶皮层）比成年人更多地代表与任务无关的信息。这些发现表明（1）注意力不会调节儿童视觉皮层的神经表征，（2）发育中的大脑可以而且确实比成熟的大脑代表更多的信息。

意义陈述 事实证明，儿童很难保持对特定信息的注意力，同时，他们可以更好地学习“干扰因素”。虽然这些是童年的关键特征，但其潜在的神经机制尚不清楚。为了填补这一关键的知识空白，我们利用功能磁共振成像探索了注意力如何塑造儿童和成人大脑中所代表的内容，同时儿童和成人都被要求只关注两件事（物体和运动）之一。我们发现，与成年人不同，成年人会优先考虑他们被要求关注的信息，而儿童既代表他们被要求优先考虑的信息，又代表他们被要求忽略的信息。这表明注意力对儿童的神经表征有着根本不同的影响。