Ethnic Fluidity as Classification Propensities: Culture, Socioeconomic Status, and Changes in Indigenous Self-Identification in Mexico

A growing body of social science research has demonstrated that ethnoracial self-identification can vary over time. This article examines the instability of Indigenous self-identification in Mexico using prototype theory, which conceptualizes classification as a graded process where individuals have different propensities to self-identify based on their proximity to a prototype. Using a nationally representative longitudinal survey spanning 10 years, this study explores factors—education, economic standing, language, and ethnic proximity—that may influence these propensities. Findings reveal that individual-level ethnic change is a prevalent phenomenon, with approximately 16% of respondents altering their Indigenous self-identification at least once during the study period. The number of Mexicans who identify as Indigenous some—but not all—of the time is about twice as large as the number of Mexicans who always identify as Indigenous. Cultural factors, such as Indigenous language use and residence in an Indigenous-majority municipality, are strongly associated with stability in Indigenous identification. In contrast, higher economic standing is associated with a lower probability of self-identification, although this effect is observed primarily among speakers of Indigenous languages. Notably, these associations reflect between-individual differences rather than within-individual changes over time. These results underscore the fluid and socially constructed nature of Indigenous identification in Mexico, highlighting the interplay of cultural and socioeconomic factors in shaping ethnoracial categorization. By integrating prototype theory with empirical analysis, this study advances our understanding of the mechanisms underlying ethnoracial fluidity and contributes to broader discussions on race and ethnicity in Latin America and beyond.