Response bias in numerosity perception at early judgments and systematic underestimation

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Kilic A., Inan A. B.

ATTENTION PERCEPTION & PSYCHOPHYSICS, vol.84, no.1, pp.188-204, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 84 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.3758/s13414-021-02365-3
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.188-204
  • Keywords: Numerosity perception, Mental number line, Speed-accuracy trade-off, Response deadline procedure, OVER-ESTIMATION, NUMBER, DISCRIMINATION, REPRESENTATION, LOUDNESS, HUMANS, CODE
  • Middle East Technical University Affiliated: Yes


Mental number representation relies on mapping numerosity based on nonsymbolic stimuli to symbolic magnitudes. It is known that mental number representation builds on a logarithmic scale, and thus numerosity decisions result in underestimation. In the current study, we investigated the temporal dynamics of numerosity perception in four experiments by employing the response-deadline SAT procedure. We presented random number of dots and required participants to make a numerosity judgment by comparing the perceived number of dots to 50. Using temporal dynamics in numerosity perception allowed us to observe a response bias at early decisions and a systematic underestimation at late decisions. In all three experiments, providing feedback diminished the magnitude of underestimation, whereas in Experiment 3 the absence of feedback resulted in greater underestimation errors. These results were in accordance with the findings that suggested feedback is necessary for the calibration of the mental number representation.