In 1969 Willis and Edwards tested 50 female participants who showed a fear of mice and used 3 conditions. Used systematic desensitisation, flooding and control group. Founf that systematic desensitisation was more successful than flooding in reducing the fear of mice the 2 therapist using sd produced similar effects from therapy. Flooding was no more effective than no therapy as experienced by control group. They found that the effects of systematic desensitisation were still present after about 7 weeks