Two’s company, three’s a crowd: Individuation is necessary for object recognition

Ramakrishna Chakravarthi* (Corresponding Author), Amy Herbert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
9 Downloads (Pure)


Object recognition is essential for navigating the real world. Despite decades of research on this topic, the processing steps necessary for recognition remain unclear. In this study, we examined the necessity and role of individuation, the ability to select a small number of spatially distinct objects irrespective of their identity, in the recognition process. More specifically, we tested if the ability to rapidly individuate and enumerate a small number of objects (subitizing) can be impaired by crowding. Crowding is flanker-induced interference that specifically impedes the recognition process. We found that subitizing is impaired when objects are close to each other (Experiment 1), and if the target objects are surrounded by irrelevant but perceptually similar flankers (Experiments 2-4). This impairment cannot be attributed to confusion between targets and flankers, wherein flankers are inadvertently included in or targets are excluded from enumeration (Experiments 3-4). Importantly, the flanker induced interference was comparable in both subitizing and crowding tasks (Experiment 4), suggesting that individuation and identification share a common processing pathway. We conclude that individuation is an essential stage in the object recognition pipeline and argue for a cohesive proposal that both crowding and subitizing are due to limitations of selective attention.
Original languageEnglish
Pages (from-to)69-82
Number of pages14
Early online date18 Dec 2018
Publication statusPublished - Mar 2019

Bibliographical note

We thank Marlene Poncet and Patrick Cavanagh for helpful suggestions on the manuscript. We thank Louise Hill for help with some of the data collection. We are grateful to the reviewers and editor for their insightful comments on the framing of the study and our interpretation of the results, which led us to rethink the implications of our findings.


  • Individuation
  • recognition
  • subitizing
  • crowding
  • enumeration
  • attention
  • Enumeration
  • Attention
  • Subitizing
  • Crowding
  • Recognition


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