A neural mechanism of speed-accuracy tradeoff in macaque area LIP

Timothy Hanks, Roozbeh Kiani, Michael N. Shadlen

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


Decision making often involves a tradeoff between speed and accuracy. Previous studies indicate that neural activity in the lateral intraparietal area (LIP) represents the gradual accumulation of evidence toward a threshold level, or evidence bound, which terminates the decision process. The level of this bound is hypothesized to mediate the speed-accuracy tradeoff. To test this, we recorded from LIP while monkeys performed a motion discrimination task in two speed-accuracy regimes. Surprisingly, the terminating threshold levels of neural activity were similar in both regimes. However, neurons recorded in the faster regime exhibited stronger evidence-independent activation from the beginning of decision formation, effectively reducing the evidence-dependent neural modulation needed for choice commitment. Our results suggest that control of speed vs accuracy may be exerted through changes in decision-related neural activity itself rather than through changes in the threshold applied to such neural activity to terminate a decision.

Original languageEnglish (US)
StatePublished - 2014
Externally publishedYes


  • decision making
  • neuroscience
  • parietal cortex
  • rhesus macaque monkey
  • speed-accuracy tradeoff

ASJC Scopus subject areas

  • Neuroscience(all)
  • Medicine(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)


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