How did Wissler use the distribution of cultural traits to estimate their age?

Clark Wissler utilized the age-area hypothesis to estimate the relative age of cultural traits by examining their geographic distribution.12

His method was based on the assumption that cultural elements tend to diffuse outward in all directions from their original point of invention. Consequently, Wissler argued that traits with the widest geographic distribution were the oldest, as they had been in the process of spreading for the longest period of time.12

To apply this, Wissler first accounted for environmental and cultural obstacles—such as geographic barriers or existing cultural patterns—that might hinder or distort the natural spread of a trait. Once these factors were considered, he inferred that the most widely dispersed elements represented the earliest innovations. While this approach provided a systematic way to analyze cultural history, it was later heavily criticized for being overly simplistic and failing to account for variables like rapid, uneven diffusion or significant population movements.21