Rational humanity? The buffet story

I read an article in the online journal PLOS One yesterday, which as we all know, publishes “in over 200 subject areas across science, engineering, medicine and the related social sciences and humanities”. You may not also know that “Multidisciplinary and interdisciplinary research, negative and null results are all in scope“, and that PLOS has an open access policy which means that you can read the articles it publishes free.

I read an article called Slim by Design: Serving Healthy Foods First in Buffet Lines Improves Overall Meal Selection, researched and written by Brian Wansink and Andrew S. Hanks, and published on October 23, 2013. Their research objective? “Each day, tens of millions of restaurant goers, conference attendees, college students, military personnel, and school children serve themselves at buffets – many being all-you-can-eat buffets. Knowing how the food order at a buffet triggers what a person selects could be useful in guiding diners to make healthier selections.”

They carried out their research by sending conference attendees to one of two seven-item buffet tables, which unknown to the subjects, had the items on them “reversed (least healthy to most healthy, and vise-versa)”.

The results caught my attention. From the abstract:

With buffet foods, the first ones seen are the ones most selected. Over 75% of diners selected the first food they saw, and the first three foods a person encountered in the buffet comprised 66% of all the foods they took. Serving the less healthy foods first led diners to take 31% more total food items (p<0.001). Indeed, diners in this line more frequently chose less healthy foods in combinations, such as cheesy eggs and bacon (r = 0.47; p<0.001) or cheesy eggs and fried potatoes (r = 0.37; p<0.001). This co-selection of healthier foods was less common.

Their conclusions?

What ends up on a buffet diner’s plate is dramatically determined by the presentation order of food. Rearranging food order from healthiest to least healthy can nudge unknowing or even resistant diners toward a healthier meal, helping make them slim by design. Health-conscious diners, can proactively start at the healthier end of the line, and this same basic principle of “first foods most” may be relevant in other contexts – such as when serving or passing food at family dinners.

Why do I mention this? It offers evidence, if we actually need more, that our “rational” choices may in fact contain little or no rationality at all. We find ourselves “nudged” in one direction or another in almost every public encounter in which we buy, consume, or decide something; without ever pausing to consider the habits and strategies that we actually use to choose our choices.

This kind of evidence has come rolling in since at least 1957 when Vance Packard wrote The Hidden Persuaders. To my surprise, we still seem to find it surprising.