Lemming's don't run off cliffs en masse. Despite the common belief that they do, nobody has ever observed them try, or do anything even remotely close. 

Likewise, you probably never in your life consume a spider. It was popular when I was younger to parrot the fact that most people will accidentally consume 3 spiders in your sleep in your lifetime. 

Some others:

• You use more than 10% of your brain
• Your tongue does not have different regions that taste things differently
• Carrots do not improve your vision at night 
• Goldfish do not have 3-second memories
• You can't see the Great Wall of China from space
• Chewing gum does not sit in your stomach for 7 years
• Napoleon was not short
• You can definitely swim after eating
• No matter what height you drop it from, a penny can't kill anyone
• Einstein did not fail maths
• You don't have to wait 24 hours before reporting someone missing
• Only infants lose most of their heat through their heads
• You can wake up sleepwalkers
• Bats have quite good eyes
• Shaving doesn't make your hair grow back longer or thicker

All of these facts are well known but all quite ridiculous and have been demonstrated to be false numerous times. Yet still, people believe them.

Researchers have identified this effect as the "illusion of truth". We knew about it in 1977. In essence, something that is familiar to an audience is viewed in a much more positive light, especially if it links with another idea that person believes.

All this would seem to suggest that if we want to get authentic, expert insights in front of our clients and have them understand it - it needs to be repeated multiple times and reinforced with other content over time. You need to earn this right with your clients and prospects. 

Sending the exact same thing over and over again will get you blocked. Sending valuable and consistent information is how you help the market understand your message.