Re:McKinsey Advised Johnson and Johnson on Increasing Opioid...
by chipperyman573 on Thursday July 25, 2019 @04:15PM
(#20529131)
This study tested kids but it supports the argument you made, and it's pretty reasonable to assume it applies to adults as well. https://www.cbc.ca/news/kids-think-food-in-mcdonald-s-wrappe...
Find a natural experiment where two very similar populations, chosen at random, were placed into two different cohorts. I'm sure there's one somewhere in the recent and well documented past.