Laboratory of Experimental Psychology, University of Leuven, Belgium.
Neuroimage. 2013 Apr 15;70:301-7. doi: 10.1016/j.neuroimage.2012.12.048. Epub 2012 Dec 30.
To investigate the difference in passive viewing and active processing of numerosity, we presented participants arrays of dots and concurrently measured their EEG. In the first condition, participants naïve to the subject under study passively viewed the dot-arrays. In the second condition, the participants were informed about the changes in numerosity and had to actively process numerosity. The visual properties of the dot-arrays were controlled and could therefore not explain possible numerosity related effects. The results revealed no numerosity related effects in the passive and active conditions. Instead, when the data was reorganised according to visual cue size (surface or diameter, etc.), strong effects of the visual cues were present at lateral occipital and parietal electrode sites. These electrode sites and time windows correspond to the ERP components often suggested to support numerosity processes. Furthermore, a larger central-parietal P3 amplitude effect was present for active versus passive numerosity processing. This result was not influenced by numerosity itself and could not be explained by response processing. It therefore appears to reflect general cognitive processes. Together, our results show that we do not (automatically) extract numerosity from a visual scene during passive or active processing of numerosity. Instead, these results are consistent with the notion that we rely on the continuous sensory properties of numerosity stimuli to make numerosity judgments.
为了探究数量的被动观察和主动处理之间的差异，我们向参与者呈现了点的数组，并同时测量了他们的脑电图。在第一种情况下，对研究主题一无所知的参与者被动地观察点数组。在第二种情况下，参与者被告知数量的变化，并必须主动处理数量。点数组的视觉属性是受控制的，因此不能解释可能与数量有关的影响。结果表明，在被动和主动条件下都没有与数量有关的影响。相反，当根据视觉线索大小（表面或直径等）重新组织数据时，在外侧枕叶和顶叶电极位置存在强烈的视觉线索效应。这些电极位置和时间窗口与经常被认为支持数量处理的 ERP 成分相对应。此外，在主动处理数量与被动处理数量时，中央顶叶 P3 振幅效应更大。这个结果不受数量本身的影响，也不能用反应处理来解释。因此，它似乎反映了一般的认知过程。总的来说，我们的结果表明，我们在被动或主动处理数量时不会（自动）从视觉场景中提取数量。相反，这些结果与我们依赖数量刺激的连续感觉属性来做出数量判断的观点是一致的。
