Why longitudinal is not developmental

In his commentary on the special issue Acculturation Reimagined, Berry (2025) questions our proposal that acculturation research could benefit from a developmental perspective, sug-gesting that such a perspective is already well established. In this response, we acknowledge that developmental ideas have long been part of acculturation research and do not claim originality for introducing them. However, we contend that merely acknowledging the value of developmental approaches, citing classical developmental theories, or relying on longitudinal designs does not realize its full potential. Indeed, one of the gravest misconceptions in the field is the assumption that measuring individuals over multiple time points is equivalent to adopting a developmental perspective. Instead, the next and much-needed step is a gen-uinely developmental–acculturation perspective with explicit conceptual and methodological integration—one that captures continuity and change across the lifespan and situates acculturation within broader developmental considerations. Our article elaborates such developmental concepts and includes, for instance, how developmental and acculturation stages are intertwined or how time in acculturative processes can be conceptualized. We illustrate how such considerations can be implemented in acculturation research, with the goal of more integrative empirical work that promotes a deeper understanding of cultural adaptation processes across the lifespan.