Getting to grips with the science behind retail on occasion can be complex and even a little unerring, as you learn about just how susceptible we are to suggestion – with music, temperature and some nicely placed colours all more than enough to convince you to part with your hard earned cash for any number of products.

But McDonald’s in Japan appear to have been taking the science of customer satisfaction down an entirely different, deeper route.

The chain designed straws specifically to ensure that drinking milkshake mimicked the speed of breastfeeding.

Reported by Rocket News, the claim was made on Twitter, and soon backed up by several people who pointed out that the founder of McDonalds in Japan, the late Den Fujita, had previously admitted the tactic in the book, Den Fujita’s Business Strategies 2: Overwhelming Business Strategies.

“When humans drink something, the speed that produces the most delicious feeling is the speed at which babies nurse…McDonald’s straws are designed so that when used with a shake, the speed will be the same as that of an infant drinking breast milk,” he wrote.

It's not clear yet if the straw was exclusively for use in Japan or was used in other nations also, or if the design is still in use.

McDonalds are yet to comment on the story.