Conditioned place preference test (Conditioned Place Preference, CPP) experiment is currently evaluating drug psychological dependence classic experimental model is widely used in the search for an effective tool of anti-drug seeking behavior. The experiment will test animals (rats, mice) in conditioned place preference box white observation area, and to give psychological dependence drugs (such as morphine), and then observe the animals conditioned place preference box in black areas and white between the activities of the district, the white areas, black areas and the gray area where free shuttle wickets for animals. Animals in each zone will be administered under the action of the drug Rewarding effects of black and white areas generating preference position, its degree of psychic dependence and drug-related.