Piazza Manuela, Giacomini Eric, Le Bihan Denis, Dehaene Stanislas
Inserm U562 NeuroImagerie Cognitive, Service Hospitalier Frédéric Joliot, CEA/DRM/DSV, 4 Place du General Leclerc, F-91401 Orsay cedex, France.
Proc Biol Sci. 2003 Jun 22;270(1521):1237-45. doi: 10.1098/rspb.2003.2356.
Theories of perception have proposed a basic distinction between parallel pre-attentive and serial attentive modes of processing. However, chronometric measures are often ambiguous in separating parallel and serial processes. We have used the activity of attention-related regions of the human brain, measured with functional magnetic resonance imaging, to separate parallel from serial processes at the single-trial level in a visual quantification task. In this task, some have suggested the deployment of two qualitatively different processes, a fast parallel 'subitizing' for sets of one, two or three objects and a slow serial counting for larger sets. Our results indicate that attention-related regions of the posterior parietal and frontal cortices show a sudden increase in activity only from numerosity four onwards, confirming the parallel-serial dichotomy of subitizing and counting. Moreover, using the presence or absence of attentional shifts, as inferred from the activation of posterior parietal regions, we successfully predict whether, on a given trial, subjects deployed a serial exploration of the display or a parallel apprehension. Beyond the subitizing/counting debate, this approach may prove useful to probe the attentional demands of other cognitive tasks.
知觉理论提出了并行的前注意加工模式和串行的注意加工模式之间的基本区别。然而，计时测量在区分并行和串行过程时往往含糊不清。我们利用功能磁共振成像测量的人类大脑中与注意力相关区域的活动，在视觉量化任务的单试次水平上区分并行和串行过程。在这个任务中，有人提出了两种性质不同的过程，一种是对一、二或三个物体集合进行快速并行的“数感”加工，另一种是对更大集合进行缓慢的串行计数。我们的结果表明，顶叶后部和额叶皮质中与注意力相关的区域仅从数量为4开始活动突然增加，证实了数感加工和计数的并行-串行二分法。此外，根据顶叶后部区域的激活推断出是否存在注意力转移，我们成功预测了在给定试次中，受试者是对显示进行串行探索还是并行感知。除了数感加工/计数的争论之外，这种方法可能被证明有助于探究其他认知任务的注意力需求。
