Since releasing the results of our survey yesterday on how Californians intend to vote on Prop 37 regarding mandatory labeling of genetically engineered food, I've received several questions from reporters regarding how consumers will respond to GE labels if retailers choose to continue using GE ingredients. I've previously written here and here on the difficulty in projecting how retailers and food manufacturers will respond if Prop 37 passes.
Relevant to the debate are actual research articles on how consumers respond to GE food labels. Here are a few abstracts from academic papers on the topic.
I'll start with a paper by your's truly in Economics Letters in 2005:
Non-hypothetical valuations obtained from experimental auctions in three United States and two European locations were used to calculate welfare effects of introducing and labeling of genetically modified food. Under certain assumptions, we find that introduction of genetically modified food has been welfare enhancing, on average, for United States consumers but not so for Europeans and while mandatory labeling has been beneficial for European consumers, such a policy would be detrimental in the United States.
I'll note that one of the places we collected data for that study was in Long Beach, California.
Here's a paper in the journal Food Policy in 2011:
In 2005, the Swiss expressed their negative attitude towards genetic engineering in agriculture by voting in favor of a ban to use genetically modified (GM) crops in domestic agriculture. At the same time, certain GM food products remain approved but are not on offer since retailers assume that consumers would shun labeled GM food. In our study we tested this claim by conducting a large-scale field study with Swiss consumers. In our experimental design, three clearly labeled types of corn bread were offered at five different market stands across the French and German-speaking part of Switzerland: one made with organic, one made with conventional, and one made with genetically modified (GM) corn. In addition, we tested the consistency between purchasing decision at the market stand and the previous voting decision on GMOs in 2005 by means of an ex-post questionnaire. The results of our discrete choice analysis show that Swiss consumers treat GM foods just like any other type of novel food. We conclude from our findings that consumers tend to appreciate transparency and freedom of choice even if one of the offered product types is labeled as containing a genetically modified ingredient. Retailers should allow consumers to make their own choice and accept the fact that not all people appear to be afraid of GM food.
Here is a paper in the journal Economics Letters in 2002
We conducted an experiment to study the discrepancy between European public opinion and consumer purchase behavior with regard to genetically modified organisms in the food supply. We found that consumers are typically unaware of the labeling indicating GMO content.
the paper also concluded:
This paper uses experimental economic methods to present evidence that the absence of a negative effect on demand in reaction to products containing GMOs is in large measure due to the fact that customers do not notice the labeling. Consumers appear not to note labels that they are not looking for in the first place.
The same authors had a paper in the Economic Journal in 2003:
We elicit willingness-to-pay information for similar food products that differ only in their content of genetically modified organisms (GMOs). Participants in the experiment are a demographically representative sample of French consumers. 35% of participants are unwilling to purchase products made with GMOs, 23% are indifferent or value the presence of GMOs, and 42% are willing to purchase them if they are sufficiently inexpensive. The results contrast with surveys that indicate overwhelming opposition to GM foods. There is a surplus to be gained from the segregation of the market for food products into a GMO-free segment and a segment allowing GMOs.