AUTHOR=Van Den Boomen Carlijn , Fahrenfort Johannes J. , Snijders Tineke M. , Kemner Chantal TITLE=Segmentation precedes face categorization under suboptimal conditions JOURNAL=Frontiers in Psychology VOLUME=6 YEAR=2015 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2015.00667 DOI=10.3389/fpsyg.2015.00667 ISSN=1664-1078 ABSTRACT=

Both categorization and segmentation processes play a crucial role in face perception. However, the functional relation between these subprocesses is currently unclear. The present study investigates the temporal relation between segmentation-related and category-selective responses in the brain, using electroencephalography (EEG). Surface segmentation and category content were both manipulated using texture-defined objects, including faces. This allowed us to study brain activity related to segmentation and to categorization. In the main experiment, participants viewed texture-defined objects for a duration of 800 ms. EEG results revealed that segmentation-related responses precede category-selective responses. Three additional experiments revealed that the presence and timing of categorization depends on stimulus properties and presentation duration. Photographic objects were presented for a long and short (92 ms) duration and evoked fast category-selective responses in both cases. On the other hand, presentation of texture-defined objects for a short duration only evoked segmentation-related but no category-selective responses. Category-selective responses were much slower when evoked by texture-defined than by photographic objects. We suggest that in case of categorization of objects under suboptimal conditions, such as when low-level stimulus properties are not sufficient for fast object categorization, segmentation facilitates the slower categorization process.