Joubert Olivier R, Fize Denis, Rousselet Guillaume A, Fabre-Thorpe Michèle
UPS, Centre de Recherche Cerveau et Cognition CNRS, CerCo, Université de Toulouse, Toulouse, France.
J Vis. 2008 Oct 31;8(13):11.1-18. doi: 10.1167/8.13.11.
Whereas most scientists agree that scene context can influence object recognition, the time course of such object/context interactions is still unknown. To determine the earliest interactions between object and context processing, we used a rapid go/no-go categorization task in which natural scenes were briefly flashed and subjects required to respond as fast as possible to animal targets. Targets were pasted on congruent (natural) or incongruent (urban) contexts. Experiment 1 showed that pasting a target on another congruent background induced performance impairments, whereas segregation of targets on a blank background had very little effect on behavior. Experiment 2 used animals pasted on congruent or incongruent contexts. Context incongruence induced a 10% drop of correct hits and a 16-ms increase in median reaction times, affecting even the earliest behavioral responses. Experiment 3 replicated the congruency effect with other subjects and other stimuli, thus demonstrating its robustness. Object and context must be processed in parallel with continuous interactions possibly through feed-forward co-activation of populations of visual neurons selective to diagnostic features. Facilitation would be induced by the customary co-activation of "congruent" populations of neurons whereas interference would take place when conflictual populations of neurons fire simultaneously.
虽然大多数科学家都同意场景背景会影响物体识别，但这种物体/背景相互作用的时间进程仍然未知。为了确定物体与背景处理之间最早的相互作用，我们使用了一种快速的“是/否”分类任务，在该任务中，自然场景会短暂闪现，受试者需要尽快对动物目标做出反应。目标被粘贴在一致（自然）或不一致（城市）的背景上。实验1表明，将目标粘贴在另一个一致的背景上会导致表现受损，而将目标隔离在空白背景上对行为的影响很小。实验2使用粘贴在一致或不一致背景上的动物。背景不一致导致正确命中次数下降10%，平均反应时间增加16毫秒，甚至影响到最早的行为反应。实验3用其他受试者和其他刺激重复了一致性效应，从而证明了其稳健性。物体和背景必须通过对诊断特征具有选择性的视觉神经元群体的前馈共同激活，并行且持续相互作用地进行处理。“一致”神经元群体的习惯性共同激活会引发促进作用，而当相互冲突的神经元群体同时放电时则会发生干扰。
