A recent study examined the effects of job demands, job control? and job social support on fatigue and intrinsic motivation among 555 nurses in specialized units for patients with different levels of mental deficiency. The investigators though that intrinsic motivation among these nures would increase when job demands and job control were high, and also when job social support was high. Further, they thought that fatigue among the nurses would be high when job demands were high and job control low, as well as when job social support was low.