Cosmetic research study: Bridging material science with social inquiry

This PhD thesis advances an interdisciplinary framework for cosmetic research by bridging materials science methodologies for hair investigation with social scientific inquiry into lived experience, identity, and wellbeing. While human hair has been extensively investigated as a keratin-based composite fibre with measurable mechanical and physicochemical properties of relevance to cosmetic products, human-centred investigations have been mostly assigned to the domains of consumer and marketing research. This body of work addresses this methodological and conceptual gap by integrating hair fibre and assembly behaviour research with studies of personal goals and perception of hair management within a unified research trajectory.

The thesis comprises six peer-reviewed publications (2018–2024) that collectively demonstrate a progression from established combing and image-based laboratory methodologies towards interdisciplinary, human-centred research designs. Early studies critically examine prevailing assumptions in hair combing and tensile testing, with subsequent work focused on artificial intelligence and computer vision techniques to assess hair assembly features, such as volume and alignment. A critical review then reports the variability of human hair from composition, geometrical and technical perspectives. The later publications extend the research scope to curlier hair types through mixed-methods social science approaches. The final publication is distinct and intentionally provocative. Rather than focusing on testing method development, it challenges dominant assumptions about beauty, vision and consumption that underpin much of the existing scholarship.

Synthesising insights from these studies, the thesis moves beyond individual methodological contributions to articulate and propose an interdisciplinary research framework for hair and cosmetic science more broadly. This framework inverts the conventional linear model of research progression, from fibre to assembly to presumed consumer benefit, by positioning lived experience at the generative starting point that guides material investigation. It outlines both theoretical and methodological principles for integrating objective material measurements with socially situated human data, thereby strengthening scientific relevance, inclusivity and wellbeing-oriented innovation.