A fascinating example of cognitive pollution. In this instance, we are talking about the persistent misinterpretation of a study on communication effectiveness performed back in the 1960's referred to as the Mehrabian study.
Here is a recent presentation talking about the importance of integrating words, delivery and body language when making a presentation: The Body Language Infographic by Nick Morgan. In it, Morgan mentions that 55% of message effectiveness depends on body language, 38% depends on the tone of voice and only 7% depends on the actual words of the presentation. These are essentially the results from Albert Mehrabian's two small studies in 1967.
Clarification and debunking is provided by Olivia Mitchell in Mehrabian and nonverbal communication.
It is important to note that the claims made regarding Mehrabian's work are entirely generated in the ether. Mehrabian himself has always been quite careful and circumscribed regarding the import of his original work.
The interesting question is why there is such prolonged and consistent misinterpretation of his work on communication? I am guessing that it is a combination of two things - 1) effective communication is universally acknowledged as a critical capacity in a modern and complex world (and consequently there is a lot of money riding on communication effectiveness), and 2) people are grasping at straws in the absence of any other data.
More simply; We regard communication effectiveness as a very important issue. We want real answers to address the real need to be more effective. We will use what's available if there's nothing else, even if we know that what's available is flawed. Basically we generate our own cognitive pollution because we like it better than simply not knowing.