On the Surplus Meanings of Numbers
Robert H. Knapp, Rachel J. C. Chen · Psychological Reports · 1964
When 40 Ss were required to select those primary digits most frequently associated with certain adjectives, there was substantial consensus in ascribing adjectives to particular digits. A factor analysis was performed based upon correlations between attributes assigned to the nine basic digits. This yielded a factor separating small from large numbers, and a second factor separating even from odd numbers. Both these factorial groupings were assigned distinctive adjectives to a significant degree.