Conference Agenda

Changing behaviours causing poor health is an ongoing global health challenge that requires developing adequate food policies and strengthening their effectiveness. Policies based on nudging have become increasingly popular internationally, but the literature provides mixed evidence of their effectiveness, with an intense academic debate. This study contributes to the debate by investigating the effect of different nudging techniques (availability enhancement, visibility enhancement and healthy eating calls) via a framed field experiment involving purchases of milk types. Participants were split into different nudging treatment groups and were endowed with a cash amount to purchase any desired quantity of the different products. We modelled observed choices via the multiple discrete–continuous nested extreme value model, which has yet to receive attention for the analysis of nudging effects on food choices. Results show that only the healthy eating call nudge effectively drove participants towards healthier milk choices, while the effect of other nudges is statistically insignificant. We provide simulated demand curves conditional on nudging treatments, which measure the effect of the latter on consumers’ consumption levels of the different milk types available.

The influence of geographical context on human behaviors and preferences has been a longstanding research focus. Studies focusing on non-market valuation have consistently emphasized the need for advancements in addressing spatial heterogeneity. This involves integrating sophisticated geographical context models sourced from diverse disciplines, highlighting the importance of cross-disciplinary research. Additionally, there is a growing recognition of the significance of spatial sampling in this context. Our study contributes to addressing these gaps, particularly within the valuation of market goods with public benefits, which has received comparatively less attention. Our primary research questions center on understanding how personal and contextual factors shape preferences for functional foods and the moderating role of regional contexts in food preferences. To address these questions, we conducted a spatially representative survey and choice experiment in Italy using pecan nuts as our study case due to their recognized health benefits. Through a multilevel framework, our analysis reveals that individual factors, including psychological and biological aspects, are the primary sources of variation in food choices across the population. Our findings confirm the heterogeneous distribution of these traits across regions and urban/rural areas, with contextual factors conditioning their effects. We emphasize the significant impact of spatial factors, highlighting that geographical location substantially shapes preferences for functional foods. These findings contribute to the stated preference literature by expanding current methodologies for controlling for spatial heterogeneity in preferences. Additionally, they provide valuable information for public initiatives promoting healthier dietary practices.

Stated preference (SP) surveys are widely used, and in many cases are the only tool available for estimating the economic value of non-market goods. However, there are important controversies about whether they provide valid welfare measures. Various approaches have been proposed to encourage truthful reporting of preferences, including the oath approach, where respondents are asked to affirm that they will answer truthfully before the survey begins. The oath approach has recently been under scrutiny because it remains uncertain whether it affects stated preferences in unintended ways. In this paper, we propose a novel approach for testing whether the oath achieves its intended purpose by comparing it to a lie detection approach, where respondents are asked to wear a device that records various bodily responses such as heart rate and skin conductance, which can be used to inform deceptive behavior. Respondents are informed that if the analyst monitoring the survey concludes that their answers are untruthful, they may be ineligible to receive a reward at the end of the survey. We compare the lie detection approach with the oath approach and a control “no-treatment” group by estimating discrete choice models using data from two experiments. We find that the maximum willingness-to-pay values for the respondents assigned to the oath treatment group and the lie detection treatment group are similar, and significantly lower than the values derived from the control group.

The discrete choice experiment (DCE) is the most common stated preference approach for estimating the economic values people place on nonmarket goods. To elicit values, the majority of DCEs use a sequence of choice questions, each with three or more choice options. Prior research demonstrates that elicited values can be sensitive to the number of choice questions and choice options; however, in a stated preference survey, beliefs about the value elicitation mechanism cannot be precisely controlled and therefore the implications of this evidence for practice are unclear. We conduct an incentivized, revealed preference experiment to compare a single binary choice (Single-BC), a sequence of binary choice (Seq-BC) questions, and a sequence of trinary choice (Seq-TC) questions. We construct mechanisms around these formats that, in theory, should motivate (most) people to truthfully reveal their preferences. We find that response patterns and willingness to pay (WTP) estimates derived from the Single-BC and Seq-BC mechanisms are statistically equal, but WTP estimates from Seq-TC are generally lower. The Seq-TC approach encourages serial status quo choices, most likely due to complexity, and is prone to strong framing effects as values people place on a good depend on the characteristics of the other good in a choice set. These behavioral patterns may offset the potential efficiency advantage of Seq-TC relative to Seq-BC.