City Research Online

Calculation efficiencies for mean numerosity

Solomon, J. A. ORCID: 0000-0001-9976-4788 & Morgan, M. J. (2018). Calculation efficiencies for mean numerosity. Psychological Science, 29(11), pp. 1824-1831. doi: 10.1177/0956797618790545


Relative numerosity is traditionally studied using texture pairs. Observers must decide which member of each pair has the greater total number of texture elements. Our textures were segregated into non-overlapping “sectors” containing between 0 and 4 elements, and our observers were asked to select the texture containing the greater average number of texture elements (i.e. per sector). If observers were more sensitive to total numerosity than average numerosity, their performances (quantified by the just-noticeable Weber fraction) should have been better when the two textures occupied the same number of sectors than when they occupied unequal numbers of sectors. However, we recorded Weber fractions between 11 and 13% for all observers in all conditions. These performances were comparable with an otherwise-ideal observer whose decisions were based on between 3 and 5 sectors in each texture. We conjecture that traditional numerosity discriminations are based on similarly small numbers of element clusters.

Publication Type: Article
Additional Information: Solomon, J.A. & Morgan, M. J., Calculation efficiencies for mean numerosity, Psychological Science pp. xx-xx. Copyright © 2018 Sage. Reprinted by permission of SAGE Publications.
Subjects: R Medicine > RE Ophthalmology
Departments: School of Health & Psychological Sciences > Optometry & Visual Sciences
SWORD Depositor:
[thumbnail of NumberEfficiency20180503.pdf]
Text - Accepted Version
Download (1MB) | Preview


Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Downloads per month over past year

View more statistics

Actions (login required)

Admin Login Admin Login