Abstract
The study of basic psychological needs has witnessed a strong revival, in part spurred by Basic Psychological Need Theory (BPNT), one of the six mini-theories within Self-Determination Theory. Empirical studies on BPNT have increased exponentially since the millennium turn, leading to refinements and extensions in theory. In this contribution we review these two decades of research in order to introduce two special issues on BPNT. We first discuss key criteria that define and identify a basic need within BPNT. We then review several need-relevant themes, highlighting advancements and trends that characterize contemporary research on BPNT. Specifically, we address potential extensions of the shortlist of basic psychological needs, the role of psychological need frustration in increasing vulnerability to maladjustment, the study of the interface between individuals’ psychological and physical needs (e.g., sleep, sex, hunger), novel insights into critical need-supportive and need-thwarting practices, and the universality (versus variability) of effects of need satisfactions and supports across demographics, psychological characteristics, and cultural contexts. We also situate each of the 19 contributions that appear in this special double-issue on BPNT within these themes, while suggesting avenues for further research on the role of basic psychological needs in motivation, adjustment, and wellness.