Segmentation precedes face categorization under suboptimal conditions

Carlijn Van den Boomen*, Johannes J. Fahrenfort, Tineke M. Snijders, Chantal Kemner

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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.

Original languageEnglish
Article number667
Number of pages14
JournalFrontiers in Psychology
Volume6
DOIs
Publication statusPublished - 26 May 2015
Externally publishedYes

Keywords

  • EEG
  • face processing
  • visual system
  • low-level vision
  • high-level vision
  • categorization
  • FIGURE-GROUND ORGANIZATION
  • TEXTURE SEGREGATION
  • OBJECT RECOGNITION
  • REVERSE HIERARCHIES
  • CORTICAL ACTIVATION
  • BINOCULAR-RIVALRY
  • VISUAL-CORTEX
  • FEEDFORWARD
  • PERCEPTION
  • POTENTIALS

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