While most ads try to highlight the best features of the brands advertised and use a positive approach, many ads try to show their competitors in a bad light using a negative approach. This kind of approach is mostly used for political advertising and especially in the USA. The ads created for US Presidential campaigns are mostly negative where opposing candidates are ruthlessly dissected. In the brutal and highly competitive atmosphere of US politics, Presidential candidates hurl defamatory accusations at one another.
Research has shown that negative approach (which often amounts to character assassination) works well in case of political advertising. It destroys the opponents. However, negative approach does not work in case of general commercial advertising.