Chapter 15 505 measures are the basis for various quantitative claims (i.e. 5x smoother, etc.). Strength and Anti-breakage Returning to the concept of “consumer language” versus “scientific language,” it is instinctive for scientists to think about hair strength in terms of the mechanical properties of fibers, and a variety of methods can be used to attain such measures (see Chapter 7). The “technical strength” of hair fibers will decline as the result of various treatments or conditions that are able to cleave strength-supporting bonds within the hair, but conversely a physical increase in strength of individual fibers necessitates the formation of additional bonding. However, the efficacy of conventional daily use products resides with surfactant surface science, rather than any reactive chemistry, and so the tensile properties of hair remain unaltered by these treatments. This said, consumers generally do not assess their hair’s strength by twisting and tugging on individual fibers in an attempt to make a relative determination. Instead, their perception seemingly arises from visual observation of broken fibers in a comb or brush (or the immediate vicinity) during the grooming process. Accordingly, in Figure 6 Wet combing results for commercial 2-in-1 shampoo products