Further research supporting the link between stimulus and association, was found by Jongh et al, who found that 73% of individuals with a fear of going to the dentist, had endured a traumatic experience. This greatly contrasts to the control group with low-dental anxiety, where only 21% had a traumatic experience. This confirms association between the stimulus (Dentristy) and the unconditioned response (pain), leads to the development of a phobia