Psychometric validation and measurement invariance of the Polish Multi-Affect Indicator across diverse demographic and occupational groups.

The Self-Determination Theory (SDT) posits that human functioning depends on the fulfillment of three basic psychological needs (BPN): autonomy, competence, and relatedness. Autonomy captures the extent to which behavior is self-endorsed and volitional, competence reflects perceived effectiveness in interacting with the environment, and relatedness concerns experiencing meaningful and supportive social connection. Need satisfaction supports motivation, well-being, and psychological growth whereas need frustration reflects active need thwarting and is associated with maladaptive functioning and psychological distress. In SDT, need satisfaction and need frustration are conceptualized as distinct rather than opposite dimensions. This distinction is consistent with the dual-process model, according to which need satisfaction fosters psychological growth and integration, whereas need frustration is linked to defensive or impaired functioning. Research on BPN has often relied on variable-centered approaches. Although useful for identifying general associations, such approaches do not capture how need satisfaction and frustration co-occur within the same person. As a result, they may obscure meaningful individual configurations of need functioning.