The factor attitude is generally considered to be among the most influential for first language (L1) attrition. Nevertheless, empirical validations have proven difficult to establish. While some studies could not find clear links between measures of attitude and L1 attrition (Hulsen, 2000; Yagmur, 1997), others showed that attitudes generated from exceptional life events strongly influenced attrition (Schmid, 2002) and that pragmatic vs. ideological motivation to emigrate and ensuing attitudes were clearly linked to L1 attrition (Ben-Rafael & Schmid, 2007). A closer examination of these studies yields a noteworthy pattern: those studies that relied on questionnaires (Hulsen, 2000, Yagmur, 1997) seemed to find no straight correlations between attitude and L1 performance, while the studies that used interviews (Ben-Rafael & Schmid, 2007; Schmid, 2002) established a clearer link between the two. The present study explores the impact of attitude – as measured through both questionnaires and interviews – on L1 attrition and second language (L2) proficiency. The quantitative analysis revealed partially significant results, thus suggesting that the factor attitude would have a limited impact on L1 attrition. Individual qualitative analyses, on the other hand, revealed important links between attitudes and the migrants’ language proficiency profiles. The article argues for a combination of methodological approaches in the study of L1 attrition and underlines the idea that individual-level analyses are well suited to capture the non-linearity of attitude and its impact on L1 attrition. These conclusions fit well with a Dynamic Systems Theory perspective in relation to the constant flux of attitude perceptions and their unpredictable role in attrition (de Bot, Lowie & Verspoor, 2007).