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The same object can be described at multiple levels of abstraction (“parka”, “coat”, “clothing”), yet human observers consistently name objects at a mid-level of specificity known as the basic level. Little is known about the temporal dynamics involved in retrieving neural representations that prioritize the basic level, nor how these dynamics change with evolving task demands. In this study, observers viewed 1080 objects arranged in a three-tier category taxonomy while 64-channel EEG was recorded. Observers performed a categorical one-back task in different recording sessions on the basic or subordinate levels. We used time-resolved multiple regression to assess the utility of superordinate-, basic-, and subordinate-level categories across the scalp. We found robust use of basic-level category information starting at about 50 ms after stimulus onset and moving from posterior electrodes (149 ms) through lateral (261 ms) to anterior sites (332 ms). Task differences were not evident in the first 200 ms of processing but were observed between 200–300 ms after stimulus presentation. Together, this work demonstrates that the object category representations prioritize the basic level and do so relatively early, congruent with results that show that basic-level categorization is an automatic and obligatory process.
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Mid-level Feature Differences Support Early Animacy and Object Size Distinctions: Evidence from Electroencephalography Decoding
Abstract Responses to visually presented objects along the cortical surface of the human brain have a large-scale organization reflecting the broad categorical divisions of animacy and object size. Emerging evidence indicates that this topographical organization is supported by differences between objects in mid-level perceptual features. With regard to the timing of neural responses, images of objects quickly evoke neural responses with decodable information about animacy and object size, but are mid-level features sufficient to evoke these rapid neural responses? Or is slower iterative neural processing required to untangle information about animacy and object size from mid-level features, requiring hundreds of milliseconds more processing time? To answer this question, we used EEG to measure human neural responses to images of objects and their texform counterparts—unrecognizable images that preserve some mid-level feature information about texture and coarse form. We found that texform images evoked neural responses with early decodable information about both animacy and real-world size, as early as responses evoked by original images. Furthermore, successful cross-decoding indicates that both texform and original images evoke information about animacy and size through a common underlying neural basis. Broadly, these results indicate that the visual system contains a mid-level feature bank carrying linearly decodable information on animacy and size, which can be rapidly activated without requiring explicit recognition or protracted temporal processing.
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- Award ID(s):
- 1942438
- PAR ID:
- 10421727
- Date Published:
- Journal Name:
- Journal of Cognitive Neuroscience
- Volume:
- 34
- Issue:
- 9
- ISSN:
- 0898-929X
- Page Range / eLocation ID:
- 1670 to 1680
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1162/jocn_a_01883
