Task-Specific Codes for Face Recognition: How they Shape the Neural Representation of Features for Detection and Individuation
Task-Specific Codes for Face Recognition: How they Shape the Neural Representation of Features for Detection and Individuation
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DOI：
10.1371/journal.pone.0003978
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发表时间：
2008-12-29
期刊：
影响因子：
3.7
通讯作者：
Tarr, Michael J.
中科院分区：
文献类型：
--
作者：
Nestor, Adrian;Vettel, Jean M.;Tarr, Michael J.
背景：人脸分类的方式多种多样，这使得人脸识别对合成视觉系统和生物视觉系统都具有挑战性。在这里，我们关注两个人脸处理任务，检测和个性化，并探索任务需求的差异是否会导致自动识别最有效的特征和神经处理招募的特征代码的差异。方法/主要发现：我们的研究呼吁将代表对象类别的特征表征为重叠图像片段集的计算框架。在这个框架内，我们评估与任务相关的信息在不同图像片段之间的差异程度。基于我们在任务特定表征之间发现的客观差异，我们测试了人类视觉系统对这些独立于彼此的不同人脸描述的敏感度。行为和功能磁共振成像都揭示了客观任务特定信息水平所产生的影响。在行为上，图像碎片的识别性能随着不同人脸碎片携带的特定任务信息的增加而提高。在神经上，这种对这两个任务的敏感性表现为腹侧视觉通路上神经反应的不同定位。诊断为检测的碎片在右侧后梭形回和双侧枕下回比非诊断的碎片引起更大的神经反应。相反，诊断为个体化的片段比非诊断的片段在前下回引起更大的反应。结论/意义：我们的结果表明：1)用于面孔检测和个性化的信息诊断大致是可分离的；2)人类视觉系统对这两种信息是独立敏感的；3)神经反应因所考虑的任务相关信息的类型而不同。更广泛地说，这些发现为基于片段的视觉表征和识别的计算效用和神经有效性提供了证据。
Background: The variety of ways in which faces are categorized makes face recognition challenging for both synthetic and biological vision systems. Here we focus on two face processing tasks, detection and individuation, and explore whether differences in task demands lead to differences both in the features most effective for automatic recognition and in the featural codes recruited by neural processing.Methodology/Principal Findings: Our study appeals to a computational framework characterizing the features representing object categories as sets of overlapping image fragments. Within this framework, we assess the extent to which task-relevant information differs across image fragments. Based on objective differences we find among task-specific representations, we test the sensitivity of the human visual system to these different face descriptions independently of one another. Both behavior and functional magnetic resonance imaging reveal effects elicited by objective task-specific levels of information. Behaviorally, recognition performance with image fragments improves with increasing task-specific information carried by different face fragments. Neurally, this sensitivity to the two tasks manifests as differential localization of neural responses across the ventral visual pathway. Fragments diagnostic for detection evoke larger neural responses than non-diagnostic ones in the right posterior fusiform gyrus and bilaterally in the inferior occipital gyrus. In contrast, fragments diagnostic for individuation evoke larger responses than non-diagnostic ones in the anterior inferior temporal gyrus. Finally, for individuation only, pattern analysis reveals sensitivity to task-specific information within the right "fusiform face area".Conclusions/Significance: Our results demonstrate: 1) information diagnostic for face detection and individuation is roughly separable; 2) the human visual system is independently sensitive to both types of information; 3) neural responses differ according to the type of task-relevant information considered. More generally, these findings provide evidence for the computational utility and the neural validity of fragment-based visual representation and recognition.