Ant colonies outperform individuals when a sensory discrimination task is difficult but not when it is easy

Takao Sasaki, Boris Granovskiy, Richard P. Mann, David J T Sumpter, Stephen Pratt

Research output: Contribution to journalArticle

50 Scopus citations


"Collective intelligence" and "wisdom of crowds" refer to situations in which groups achieve more accurate perception and better decisions than solitary agents. Whether groups outperform individuals should depend on the kind of task and its difficulty, but the nature of this relationship remains unknown. Here we show that colonies of Temnothorax ants outperformindividuals for a difficult perception task but that individuals do better than groups when the task is easy. Subjects were required to choose the better of two nest sites as the quality difference was varied. For small differences, colonies were more likely than isolated ants to choose the better site, but this relationship was reversed for large differences. We explain these results using a mathematical model, which shows that positive feedback between group members effectively integrates information and sharpens the discrimination of fine differences. When the task is easier the same positive feedback can lock the colony into a suboptimal choice. These results suggest the conditions under which crowds do or do not become wise.

Original languageEnglish (US)
Pages (from-to)13769-13773
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number34
StatePublished - Aug 28 2013



  • Biological complexity
  • Group cognition
  • Psychophysics
  • Social insects

ASJC Scopus subject areas

  • General

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