This study investigates the job demands-resources (JD-R) model in relation to work motivation in a self-determination theory (SDT) perspective, with the purpose of developing a model where social-contextual factors are seen in relation to psychological needs in order to explain autonomous work motivation and, in turn, self-reported work performance and somatic symptom burden. SEM-analyses of cross-sectional survey data including 405 waiters/waitresses in Norway were conducted to evaluate the hypothesized model. Results indicate that different job resources have different relations to psychological need satisfaction, and that certain types of job demands (i.e., job challenges) actually may enhance satisfaction of specific psychological needs. In particular, task autonomy had a positive relation to autonomy satisfaction (p < .001) and to competence satisfaction (p < .05), positive feedback had a positive relation to autonomy-, competence-, and relatedness satisfaction (p < .001), and workload had a positive relation to competence satisfaction (p < .001). Furthermore, psychological needs for autonomy, competence, and relatedness positively related to autonomous work motivation and, in turn, positively to work performance and negatively to somatic symptom burden (p < .001). Indirect relations were also detected between the job characteristics and autonomous work motivation and between the basic needs and work performance (p < .05). Hence, when explaining autonomous work motivation and work outcomes, it is important to distinguish between different job demands and job resources, as well as among the three psychological needs.
Keywords: job characteristics; motivation; performance; psychological needs; somatization.