In the world of advertising, there are different types of content. Propositional content makes specific claims about a product which can be objectively assessed as either true or false. Non-propositional content utilises tools such as imagery, music and positive emotions to influence viewers, but cannot be objectively judged as correct or incorrect.

Advertisers can make use of non-propositional content to elicit positive feelings from their viewers. This is called evaluative conditioning and can create positive beliefs about a drug’s safety and efficacy. For example, an advertisement for an antiplatelet drug used the by-line “save even more lives” rather than “reduce mortality”.

Read the full article here to see how health care professionals need to be mindful of subliminal messages, bearing in mind that in 2005 drug companies spent nearly half a billion US dollars on advertising in journals which generated a return of about $5 for every dollar spent.