Sometimes who says it matters more than what's said.
The same message can be valued differently depending on who communicates it. If it comes from someone we respect, it's more likely to influence our decision. If it comes from someone we don't value, we tend to dismiss it, no matter how valid the content is.
During the post-lockdown period of the COVID-19 pandemic, an in-house study by Heurística Lab (2020) tested whether the same message about attending social gatherings changed its effect depending on who issued it. The message sent by the Ministry of Health reduced willingness to attend a social gathering by 19%, compared to the same message issued by a best friend. An iconic example of the same principle, in a positive sense, is Steve Jobs as Apple's spokesperson for years, personally presenting products like the iPhone or the iPad.
We don't evaluate a message only by its content, but also by who's delivering it. The perceived credibility, closeness, or authority of the messenger changes how much weight we give to what they say.
Source: Heurística Lab (2020). Experimental survey: Evaluation of the presence of the "messenger effect" and the evaluation of stimuli "grouped vs. individual" in the context of the COVID-19 pandemic.
There's no universally ideal messenger. A public health notice, a savings campaign, or an internal communication work differently depending on whether they come from an authority, a close peer, or an opinion leader, and that has to be decided based on the real audience of each message.
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