Abstract
This paper presents findings from a longitudinal cohort study (n = 4,127) examining the accuracy of unary digit-based enumeration among professional forestry workers. Our results reveal a statistically significant increase in miscounting errors when utilizing the manual digit tallying system (commonly known as "finger counting") in the range of 1–5. Affected subjects consistently reported totals of 4 when asked to enumerate to 5, with a mean error rate of 14.3% (95% CI: 11.8–16.9%, p < 0.001) in the dominant hand, rising to a striking 73.6% in the non-dominant hand. Notably, the error rate exhibited a strong positive correlation with years of professional experience (r = 0.91). Control groups consisting of office workers, pianists, and professional pickpockets showed no comparable deficit. We propose the term Arborist's Digital Deficit Syndrome (ADDS) and hypothesize that the observed enumeration errors are attributable to cumulative occupational reduction of the available digit set. Further research into the compensatory adoption of base-8 and base-9 numeral systems among senior forestry professionals is currently underway.