Adaptive spontaneous transitions between two mechanisms of numerical averaging

Noam Brezis, Zohar Z. Bronfman, Marius Usher

Research output: Contribution to journalArticlepeer-review


We investigated the mechanism with which humans estimate numerical averages. Participants were presented with 4, 8 or 16 (two-digit) numbers, serially and rapidly (2 numerals/second) and were instructed to convey the sequence average. As predicted by a dual, but not a single-component account, we found a non-monotonic influence of set-size on accuracy. Moreover, we observed a marked decrease in RT as set-size increases and RT-accuracy tradeoff in the 4-, but not in the 16-number condition. These results indicate that in accordance with the normative directive, participants spontaneously employ analytic/sequential thinking in the 4-number condition and intuitive/holistic thinking in the 16-number condition. When the presentation rate is extreme (10 items/sec) we find that, while performance still remains high, the estimations are now based on intuitive processing. The results are accounted for by a computational model postulating population-coding underlying intuitive-averaging and working-memory-mediated symbolic procedures underlying analytical-averaging, with flexible allocation between the two.

Original languageEnglish
Article number10415
JournalScientific Reports
StatePublished - 4 Jun 2015


Dive into the research topics of 'Adaptive spontaneous transitions between two mechanisms of numerical averaging'. Together they form a unique fingerprint.

Cite this