The idea that you need to repeat a message to get through to people is hardly new.

In fact, there's an urban legend (not based on science) that an audience member needs to "hear" an advertiser's message at least 7 times before taking action to buy that product or service. 

So you may ask yourself: Is repetition really a thing? And, if so, how repetitive should I be to make my message stick?

Luckily, science has the answers you need, according to John Medina, author of Brain Rules

"The typical human brain can hold about seven pieces of new information for less than 30 seconds," Medina writes. "If something does not happen in that short stretch of time, the information becomes lost. If you want to extend the 30 seconds to, say, a few minutes, or even an hour or two, you need to consistently re-expose yourself to the information."

But, because of the way the brain works, simply repeating information--Here's this! Here it is again! And again! And one more time!--is not effective, explains Medina. Instead, brain researchers recommend that you do these three things to make your message really stick:

1. Share information sparingly. Put down that firehose! "Much like concrete, memory takes an almost ridiculous amount of time to settle into its permanent form," Medina writes. "While memory is hardening, it is maddeningly subject to amendment. Such interference is likely to occur when we encounter an overdose of information without breaks, much like what happens in most conferences or classrooms." 

In other words, those long, dense PowerPoint presentations are exactly the wrong way to share information so audience members remember what you presented. (In fact, data-filled PPTs are a terrible way to get and hold people's attention.) Yes, you'd like to tell the complicated story of how you came up with your brilliant recommendation, but--sorry--people neither care nor will they recall those details. So hone down your content to the essence.  

2. Repeat your messages at deliberate intervals.The interference that Medina refers to doesn't occur if information is built up slowly, repeated in deliberately spaced cycles. 

"Repetition cycles add information to our knowledge base," he writes. "The timing of repetitions is a key component. This was demonstrated by German researcher Hermann Ebbinghaus more than 100 years ago. He showed that repeated exposure to information in spaced intervals provides the most powerful way to fix memory in the brain."

This type of repetition is called maintenance rehearsal. It is good for keeping things in working memory--that is, for a short period of time. (For longer retention, keep reading to #3.)

3. Create opportunities to participate. To move information into long-term memory, you need to tap into a brain mechanism called elaborative rehearsal. Medina writes that "a great deal of research shows that thinking or talking about an event immediately after it has occurred enhances memory for that event, even when accounting for differences in type of memory.

That means that you need people to do something in order to process your message thoroughly enough to retain it. How to?

  • If you're sharing information in person, facilitate an exercise in which audience members work with the topic. Ask them questions about how your topic relates to their experience. And encourage them to ask questions.
  • If you're online, encourage people to take an action. Create an interactive experience, like a quiz. Provide an incentive for exploring further.

Remember this: The relationship between repetition and memory are clear. "Deliberately re-expose yourself to information if you want to retrieve it later," writes Medina.

"Deliberately re-expose yourself to information more elaborately if you want to remember more of the details. Deliberately re-expose yourself to the information more elaborately and in fixed, spaced intervals if you want the retrieval to be as vivid as possible." And if you're trying to make your message stick, use this process with your audience.