I want to add a clarification and caveat to that statement. What we found (in the context of an internet survey), is that the addition of GMO labels didn't make people more concerned about GMOs than they already were. That is, the addition of a label didn't seem to send a signal that GMOs were more risky than consumers already thought they were.
However, we did find that consumers would attempt to avoid foods with a GMO label. Consumers' choices in our studied implied they were willing to pay as much $1.98/lb to avoid an apple that has a mandatory "genetically engineered" label relative to an unlabeled apple. As I discussed just yesterday, it is precisely this issue that is the big potential driver of the costs of mandatory labeling. That is, if some segment of consumers tries to avoid GMO labels, retailers and food manufacturers may respond by trying to source more costly non-GMO crops.
Finally, I'll note that despite the above quote, that different types of GE labels in fact had very big effects on what people "thought" or were willing to pay for GE foods. In particular, we compared how willingness-to-pay (WTP) for an unlabeled apple varied when there were apples with mandatory labels (i.e., "genetically engineered) vs. voluntary labels (i.e., "not genetically engineered").
We found that the WTP premium for the unlabeled apple relative to the apple labeled "genetically engineered" was the aforementioned $1.98/lb. However, the WTP premium for apples labeled "not genetically engineered" relative to the unlabeled apple was only $0.81/lb. Thus, the implied willingness-to-pay to avoid GE was [(1.98–0.81)/0.81] ∗ 100 = 144% higher in the mandatory labeling treatment as compared to the voluntary labeling treatment. In the paper, we write:
One more point that I just can't led slide. The editorial also mentions the following:
Yes, but about the same percentage of consumers say they want mandatory labels on foods with DNA. And, when you directly ask people, the vast majority say they don't want the issue decided by state ballot initiatives but rather by the FDA. And, we've had real-life ballot initiatives in five states now, and all have failed to garner more than 50% support. Whatever positive reasons may exist for mandatory labeling, the cited "90% of people want it" reason is the most dubious and misleading.