Hi, My learned friend who has an Oxford Msc and PhD in science has recently cited this link as proving that rats find sugar (sucrose) more addictive than cocaine and thus that it could also be highly addictive to humans in the same way. I was used to setting up and critiquing simple psychology experiments at university and was always aware that nothing is proved without a suitable control experiment. In this case I have not been able to find any situation you describe which proves that the rats are not avoiding the cocaine (in my opinion a sensible choice) rather than making a positive sugar choice: to "get a high". Such a control could be a choice between cocaine and another liquid or substance that is pleasant but not suspected to be addictive for rats. Please can you explain where your version of such a control exists in this experiment?