Institute of Neurosciences and Medicine (INM-3, INM-1), Research Centre Juelich, Juelich, Germany.
Cortex. 2011 Jul-Aug;47(7):854-62. doi: 10.1016/j.cortex.2010.08.001. Epub 2010 Aug 11.
Our visual world is hierarchically organized. Hierarchical processing is frequently investigated using Navon figures (large letters made up of smaller ones). In young adults, many studies reported faster reaction times (RT) to target letters presented at the global level [i.e., global precedence (GP)]. Furthermore, an age-related decline of this GP has been reported. We tested whether deficits in perceptual grouping via Gestalt laws (Gestalt principles of Proximity and Continuity) might contribute to this decline. In a directed attention task with valid and invalid cues, 20 young (mean age 22) and 20 older (mean age 57) male subjects had to indicate whether a target letter appeared at the global or local level of a Navon figure. The number of local letters forming the global figure was modulated in 5 steps. As expected, during valid trials, young adults showed a GP that linearly increased with increasing numbers of local letters (i.e., GP enhancement). This suggests that GP is related to perceptual grouping via Gestalt laws. By contrast, the group of older subjects demonstrated no precedence effect in RT and a non-significant trend toward GP in error rates (ER). No GP enhancement with an increasing number of local elements was observed. Exploratory analysis revealed that individual insensitivity to the modulation of matrix density, as revealed by a lack of global RT acceleration, was restricted to subjects that showed an overall local precedence (LP). Because older subjects tended to more frequently display an insensitivity to matrix modulation and an LP, we conclude that deficient Gestalt detection as indicated by non-enhanced global RT might contribute to the RT-related decline of GP with age.
我们的视觉世界是分层组织的。使用纳冯图形（由较小的字母组成的大字母）经常研究分层处理。在年轻人中，许多研究报告称，目标字母在全局水平上呈现时反应时间（RT）更快[即全局优先（GP）]。此外，据报道，这种 GP 随着年龄的增长而下降。我们测试了通过格式塔定律（接近和连续性的格式塔原则）进行的知觉分组缺陷是否可能导致这种下降。在带有有效和无效线索的定向注意任务中，20 名年轻（平均年龄 22 岁）和 20 名年长（平均年龄 57 岁）男性受试者必须指出目标字母是否出现在纳冯图形的全局或局部水平。形成全局图形的局部字母的数量以 5 个步骤进行调制。正如预期的那样，在有效试验中，年轻人表现出 GP，随着局部字母数量的增加呈线性增加（即 GP 增强）。这表明 GP 与通过格式塔定律进行的知觉分组有关。相比之下，年长组在 RT 中没有表现出优先效应，在错误率（ER）中也没有表现出 GP 的非显著趋势。随着局部元素数量的增加，没有观察到 GP 增强。探索性分析表明，个体对矩阵密度调制的不敏感，表现为全局 RT 加速不足，仅限于表现出整体局部优先（LP）的受试者。由于年长的受试者往往更频繁地表现出对矩阵调制和 LP 的不敏感，因此我们得出结论，缺乏全局 RT 增强所表示的 Gestalt 检测可能导致 GP 随年龄增长的 RT 相关下降。
