Enumerating the forest before the trees: The time courses of estimation-based and individuation-based numerical processing

David Melcher, Christoph Huber-Huber, Andreas Wutz

Research output: Contribution to journalArticlepeer-review


Ensemble perception refers to the ability to report attributes of a group of objects, rather than focusing on only one or a few individuals. An everyday example of ensemble perception is the ability to estimate the numerosity of a large number of items. The time course of ensemble processing, including that of numerical estimation, remains a matter of debate, with some studies arguing for rapid, “preattentive” processing and other studies suggesting that ensemble perception improves with longer presentation durations. We used a forward-simultaneous masking procedure that effectively controls stimulus durations to directly measure the temporal dynamics of ensemble estimation and compared it with more precise enumeration of individual objects. Our main finding was that object individuation within the subitizing range (one to four items) took about 100–150 ms to reach its typical capacity limits, whereas estimation (six or more items) showed a temporal resolution of 50 ms or less. Estimation accuracy did not improve over time. Instead, there was an increasing tendency, with longer effective durations, to underestimate the number of targets for larger set sizes (11–35 items). Overall, the time course of enumeration for one or a few single items was dramatically different from that of estimating numerosity of six or more items. These results are consistent with the idea that the temporal resolution of ensemble processing may be as rapid as, or even faster than, individuation of individual items, and support a basic distinction between the mechanisms underlying exact enumeration of small sets (one to four items) from estimation.

Original languageEnglish (US)
Pages (from-to)1215-1229
Number of pages15
JournalAttention, Perception, and Psychophysics
Issue number3
StatePublished - Apr 2021


  • Object recognition
  • Scene perception
  • Temporal processing

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Language and Linguistics
  • Sensory Systems
  • Linguistics and Language


Dive into the research topics of 'Enumerating the forest before the trees: The time courses of estimation-based and individuation-based numerical processing'. Together they form a unique fingerprint.

Cite this