Fingerprint pattern factors

Factor analysis was employed using the ulnar ridge count, radial ridge count, ridge count (the larger of the radial or ulnar count as generally used for calculating total ridge count), and pattern type for each finger in 720 twins. Pattern type and ulnar count displayed parallel factor loadings while loadings for radial and ridge count also paralleled each other. This relationship did not hold for the index finger, indicating the importance of pattern direction and greater pattern diversity for this digit. Total ridge count was most closely associated with a factor of ring and little finger radial and ridge count and only secondarily with an index finger factor. When radial and ulnar counts were deleted to make comparisons with earlier studies, the result was factors having groupings of variables identical with previous reports. It appears that factor analysis results in consistent extraction of identical or very similar factors from different populations, and the use of radial and ulnar counts adds more information than when only the larger of the two counts is considered.