The fact that most of these studies may not necessarily tell us about *net* reduction. Anecdotally, back when I ate meat, I'd be the first one to bail (and take my friends with me) if I saw the cafeteria didn't serve meat.
I agree -- in particular, I think behavioral spillover (potentially both good and bad) is the biggest set of unanswered questions in defaults as an intervention.
Great read! It would be interesting to see if low-meat/low-impact defaults instead of JUST purely plant-based defaults would help offset this issue - "some likely opting for meat dishes at other stations in the cafeteria."
They alter spoon size at a meat serving station at lunch and then measure effects at dinner as well (intertemporal spillovers). They find that a small reduction in spoon size changes behavior some, but a larger reduction causes people to ask for more spoonfuls, which basically cancels the effect out. (Neither effect is significant)
Really cool! This is something I hadn't thought about. Thanks for sharing.
Which part, the general challenge of figuring out your core outcome or interest or the specifics of figuring out if a default study ‘worked’?
The fact that most of these studies may not necessarily tell us about *net* reduction. Anecdotally, back when I ate meat, I'd be the first one to bail (and take my friends with me) if I saw the cafeteria didn't serve meat.
I agree -- in particular, I think behavioral spillover (potentially both good and bad) is the biggest set of unanswered questions in defaults as an intervention.
Yep! I really like the way this paper handles it https://arxiv.org/pdf/2504.02899v1
(Plan to write on that next, but there was enough going on in this post already 😃)
I love that study! Relatedly, have you seen a piece I wrote on defaults around this time last year? I talked a bit about behavioral spillover. https://faunalytics.org/tactics-in-practice-the-science-of-plant-based-defaults-and-nudges/
Yep, I actually link to it in the sentence "Here are two examples from the [defaults literature](https://faunalytics.org/tactics-in-practice-the-science-of-plant-based-defaults-and-nudges/)." That piece was very helpful in assembling the dataset for a previous paper 😃
Oh brilliant! Didn't catch that -- so glad the resource was helpful!
Great read! It would be interesting to see if low-meat/low-impact defaults instead of JUST purely plant-based defaults would help offset this issue - "some likely opting for meat dishes at other stations in the cafeteria."
Great question! Here’s a paper from some HSFL colleagues that modifies portion sizes to reduce meat: https://pubmed.ncbi.nlm.nih.gov/40241017/
They alter spoon size at a meat serving station at lunch and then measure effects at dinner as well (intertemporal spillovers). They find that a small reduction in spoon size changes behavior some, but a larger reduction causes people to ask for more spoonfuls, which basically cancels the effect out. (Neither effect is significant)