The “Chicken or Egg” Causality Dilemma in Second Language Acquisition: Evidence From Late‐Life Language Learning

Abstract Although research shows that motivation, well‐being, and cognition support second language (L2) success in older adults, few studies have examined whether L2 achievement feeds back into these individual differences or tracked how they interact dynamically over time. This study investigated causal links between socio‐affect (motivation, well‐being), cognition (working memory, executive function), and L2 development in 28 learners (aged 64–74) of Spanish, using 32 assessments over 8 months. Granger causality (GC) tested directional effects, and psychological network analysis (PNA) examined time‐based interactions. The results demonstrated that L2 performance—especially fluency and overall proficiency—drives subsequent motivation and working memory, whereas well‐being supports L2 growth indirectly through cognitive stimulation, revealing a dynamic, bidirectional system in which linguistic success, cognition, and socio‐affective variables mutually influence one another.