Simonsohn, U., Montealegre, A., & Evangelidis, I. (2025). Stimulus Sampling Reimagined: Designing Experiments with Mix-and-Match, Analyzing Results with Stimulus Plots. Journal of Personality and Social Psychology, 129 (1), 71-90.
Abstract
Stimuli selection in psychology experiments is typically unsystematic, undocumented, and irreproducible. This makes confounds likely to arise. The statistical analysis of psychology experiments with multiple stimuli, in turn, is typically reported at the aggregate level, averaging across stimuli. This makes confounds unlikely to be detected. Here we propose changing both the design and analysis of psychology experiments. We introduce "Mix-and-Match", a procedure to systematically and reproducibly stratify-sample stimuli, and "Stimulus Plots", a visualization to report stimulus-level results, contrasting observed with expected variation. We apply both innovations to published studies demonstrating how things would be different with our reimagined approach to stimulus sampling. Lastly, we introduce a Mix-and-Match Disclosure Form we propose authors rely on to communicate the design of their studies.
Overton, G., Evangelidis, I., & Vosgerau, J. (2025). People Believe If 90% Prefer A over B, A Must Be Much Better than B. Are They Wrong? Journal of Consumer Research, 52 (1), 135–156.
Abstract
We show that consumers confuse consensus information in polls—such as 90% prefer product A over product B—with differences in liking—the extent to which poll respondents like A better than B. Consequently, they interpret a 90% consensus in favor of A as the average liking of A being considerably higher than the average liking of B. We demonstrate empirically and with simulations that—while this can be true—it is more probable that the average liking of A is only slightly higher than that of B. This regularity is robust to the sign and size of the correlation between ratings for A and B, and across most distributions for A and B’s liking. Consumers are not aware of this regularity and believe that 90% consensus implies A being much better than B. Communicators (marketers, managers, public policy makers, etc.) can capitalize on these erroneous inferences and strategically display preference information as consensus or as liking ratings, leading to dramatic shifts in choices. Consumers’ erroneous inferences can be corrected by educating them about the shape of the distribution of liking differences. We discuss theoretical and managerial implications for the understanding and usage of polls.
Evangelidis, I., Jung, M. H., & Moon, A. (2025). The Measurement of Valuation. Consumer Psychology Review, 8 (1), 51–59.
Abstract
Researchers often wish to understand how much consumers value a product. To do this, they need to decide on the best way to determine these valuations. Past research in social sciences has developed various elicitation tasks to capture valuations. In this paper, we review that research and offer guidelines for best practices in measuring valuations. We begin with a discussion of the challenges in gauging valuations. We then critically review the different methods for measuring valuations, discussing the strengths and limitations of each. From this review, we develop guidelines for designing studies to assess valuations. Our guidelines focus on three key considerations: (1) selecting the sample for eliciting valuations, (2) determining how to present information to participants, and (3) taking into account research goals and constraints. Our aim is to improve the quality of studies measuring valuations, helping researchers draw more accurate inferences from their work.
Evangelidis, I. (2024). Shrinkflation Aversion: When and Why Product Size Decreases are Seen as More Unfair Than Equivalent Price Increases. Marketing Science, 43 (2), 280–288.
Abstract
Consumers worldwide have been struggling to keep up with rising costs of living. While many firms have (directly) increased their prices, others have engaged in the practice of product downsizing—decreasing the size or quantity of the product without changing its price. In this research, I investigate consumers’ beliefs about the fairness of product downsizing compared with equivalent price increases (i.e., holding the price per unit of product constant). Five pre-registered experiments demonstrate that, while the vast majority of people judge price increases in response to cost increases as fair, this pattern is attenuated—or even reversed—for product downsizing. Consequently, the proportion of consumers who view product downsizing as unfair is greater than the proportion who view an equivalent price increase as unfair. This phenomenon, referred to as “shrinkflation aversion,” is predominantly driven by consumers’ beliefs that product downsizing (vs. price increases) is a deceptive practice. Importantly, I provide empirical evidence for two key moderators of the phenomenon: (1) the transparency of the product change and (2) the presence (vs. absence) of increases in the firm’s costs.
Evangelidis, I. , & Bhatia, S., Levav, J., & Simonson, I. (2024). 50 Years of Context Effects: Merging the Behavioral and Quantitative Perspectives. Journal of Consumer Research, 51 (1), 19–28.
Abstract
Over the past 50 years, consumer researchers have presented extensive evidence that consumer preference can be swayed by the decision context, particularly the configuration of the choice set. Importantly, behavioral research on context effects has inspired prominent quantitative research on multialternative decision-making published in leading psychology, management, economics, and general interest journals. While both streams of research seem to agree that context effects are an important research area, there has been relatively limited interaction, communication, and collaboration between the two research camps. In this paper, we seek to initiate an active dialogue between the two sides. We begin by providing a critical overview of the two literatures on context effects, discussing both their strengths and weaknesses, as well as disparities and complementarities. Here we place particular emphasis on deepening consumer researchers’ understanding of context effects by drawing on prominent quantitative research published in non-marketing journals over the last decades. Importantly, we provide a roadmap for the future that can inspire further research and potential collaborations between the two camps, overcoming silos in knowledge creation.
Evangelidis, I. , & Gunadi, M. P. (2024). How Elicitation Procedure Shapes Beliefs about Others' Affective Responses to Action and Inaction. Personality and Social Psychology Bulletin, 50 (12), 1711–1724.
Abstract
Humans have long pondered the distinction between action and inaction. Classic work in social sciences provides evidence that most people believe that others experience higher levels of affect when they obtain the same outcome through action as opposed to inaction. In this paper, we theorize that people’s attributions of affect to identical outcomes resulting from action versus inaction are largely constructive in nature, such that they heavily depend on the elicitation procedure. Seven preregistered studies demonstrate that most individuals cease to attribute greater affect to identical outcomes resulting from action as opposed to inaction when it is made possible—or salient—that they can state that action and inaction are associated with equal levels of affect. Consequently, the present studies suggest that researchers can reach different conclusions about participants’ general proclivity to attribute greater affect to identical outcomes resulting from action (vs. inaction) depending on how participants’ beliefs are measured.
Evangelidis, I. (2024). Task Sensitivity and Noise: How Mechanical Properties of Preference Elicitation Tasks Account for Differences in Preferences Across Tasks. Decision, 11 (2), 283–302.
Abstract
Researchers can measure preference using different elicitation tasks. In this paper, I propose that the decision how to measure preference is particularly consequential because preference elicitation tasks differ in terms of two properties: (1) their sensitivity to the relative utility of the options and (2) the amount of noise in participants’ responses. I focus on two elicitation tasks: choice and ratings. Through simulations and a series of experiments, I provide robust evidence that a greater percentage of participants prefer “advantaged” options (i.e., options carrying a higher amount of utility) in choice than in rating. This typically occurs because choice is more sensitive to utility differences than ratings and because ratings are sometimes associated with higher levels of noise than choice. Further, I discuss four moderators of the effect: the granularity of the rating scale, the type of judgment elicited by the rating task, the magnitude of the utility difference between the options, and the mode by which alternatives are presented (joint vs. separate).
Evangelidis, I., Levav, J., & Simonson, I. (2023). The Upscaling Effect: How the Decision Context Influences Tradeoffs between Desirability and Feasibility. Journal of Consumer Research, 50 (3), 492–509.
Abstract
Purchase decisions typically involve tradeoffs between attributes associated with desirability (e.g., quality) and feasibility (e.g., price). In this paper we examine how the decision context impacts consumers’ preference between a high-desirability (HD) option and a high-feasibility (HF) alternative. Nineteen studies demonstrate a novel context effect, the “upscaling effect,” whereby introducing a symmetrically dominated decoy option to a set (i.e., an option that is inferior compared to all alternatives in the set) leads to an increase in the choice share of the HD option. To account for the upscaling effect, we advance a two-stage model of consumer decision-making for decisions that involve tradeoffs between desirability and feasibility. According to our model, when the decision context provides a reason for choosing either option, such as when a decoy option is added to the set, consumers prioritize reasons that support choice of HD options over HF alternatives. Our model can explain the upscaling effect, as well as other findings reported in the literature, such as asymmetric attraction effects (Heath and Chatterjee 1995) and asymmetric sales promotion effects (Blattberg and Wisniewski 1989). Further, the upscaling effect holds important managerial implications because it provides an effective way to increase sales of high-end products.
Evangelidis, I., Levav, J., & Simonson, I. (2023). A Reexamination of the Impact of Decision Conflict on Choice Deferral. Management Science, 69 (5), 2691–2712.
Abstract
In this research we reexamine and update prior research on the association between decision conflict and choice deferral. Decision conflict has featured prominently in psychology literature, going back to the seminal work of Lewin (1935), Miller (1944), and Janis and Mann (1977). Building on this earlier work and the assumption of conflict as an inhibitor of choice, Tversky and Shafir (1992; see also Dhar, 1997) argued that the tendency to defer a decision can increase when decision-makers experience conflict because of the need to make trade-offs between options in a set. Tversky and Shafir (1992) showed that decision-makers may defer choice more when faced with two options presenting trade-offs compared to when they are offered either a single option (see also Dhar 1997) or two options where one alternative dominates the other. Relatedly, Luce (1998) showed that decision-makers may be more likely to defer choice when faced with multiple options presenting relatively difficult (vs. easy) trade-offs. We reexamine published data and report the results of 40 well-powered direct and conceptual replications of these effects (total n = 26,703) that cast doubt on the replicability of prior research. Our data suggest that additional research is needed in order to reveal a robust association between experimental manipulations of decision conflict and choice deferral. We conclude our investigation by delineating a set of directions for future research on this topic.
Evangelidis, I. (2022). Rapidly Diminishing Sensitivity and Discrete Sensitivity: Explaining People's Sensitivity to Outcomes Across Decisions. Journal of Experimental Psychology: General, 151 (9), 2115–2127.
Abstract
Classic theories of perception, cognition, and judgment and decision-making assert that people exhibit diminishing sensitivity to magnitude changes. For instance, according to Prospect Theory’s value function, the pleasure of moving from 0 to $1000 is larger than the pleasure of moving from $1000 to $2000, while the pleasure of moving from $1000 to $2000 is larger than the pleasure of moving from $2000 to $3000. In this paper, I call into question how much diminishing sensitivity actually impacts choice, as well as the nature of the value function. I advance a special form of diminishing sensitivity, rapidly diminishing sensitivity, which postulates that people are sensitive to the presence versus absence of outcomes, but are rather insensitive to the scope of the outcomes when the latter differ from zero. Rapidly diminishing sensitivity yields a value function that flattens out rapidly as we move away from zero. In the special case where the value function flattens out immediately after zero, rapidly diminishing sensitivity assumes a discrete form that I coin discrete sensitivity. I propose that rapidly diminishing sensitivity and discrete sensitivity are typically observed in experimental studies that involve extensive manipulations of the size of the outcomes across decisions, while holding everything else constant. I provide evidence for my hypothesis in 8 well-powered preregistered experiments across a wide range of domains, such as financial decisions, valuations of human lives, purchase decisions, judgments of goal-related performance, intertemporal choices, and moral decisions.
Gunadi, M. P., & Evangelidis, I. (2022). The Impact of Historical Price Information on Purchase Deferral. Journal of Marketing Research, 59 (3), 623–640.
Abstract
In this paper, the authors examine how historical price information influences consumers’ decision to defer a purchase. They focus on two aspects of historical price information: the direction and the frequency of past price changes. The authors advance a theoretical framework which postulates that the interaction between these two factor shapes consumers’ decisions to buy now versus later. Controlling for the total magnitude of price changes, the authors propose that consumers are more likely to defer purchase when the price of the product has previously increased compared to when the price has decreased. Importantly, the authors hypothesize that this effect is more pronounced when consumers observe a single large change in price (e.g., an increase of $100 versus a decrease of $100) compared to when they observe multiple smaller changes that establish a trend (e.g., four decreases of $25 versus four increases of $25). The authors argue that these effects are driven by differences in consumers’ expectations about future prices. They test their predictions, as well as two moderators of the proposed effects—the monotonicity and the timing of price changes—in six well-powered pre-registered experimental studies (N = 5,713) using both hypothetical and actual purchases.
Evangelidis, I., & van Osselaer S. (2019). Interattribute Evaluation Theory. Journal of Experimental Psychology: General, 148 (10), 1733–1746.
Abstract
In this article we advance a theory that describes how people evaluate attribute values. We propose that evaluations involve a target and a reference value. Evaluators first seek a reference value on the target attribute (e.g., an average value or another stimulus’s value on that same attribute). However, in the absence of same-attribute information, evaluators may instead rely on the target stimulus’s own value on another attribute and make an evaluation about the target in one of two ways. First, the individual may compare the target attribute value to the stimulus’s value on a reference attribute. The evaluator is more likely to engage in an interattribute comparison when the target attribute value is relatively evaluable and compatible with the reference value. Second, the individual may infer the magnitude of the target value based on his or her judgment about the extremity (e.g., the goodness or badness) of the stimulus’s value on a reference attribute and the perceived correlation between the target attribute and the reference attribute. The evaluator is more likely to make an inference about the target value based on the reference when the target is low in evaluability and is less compatible with the reference value. Two attribute values are considered to be more compatible when their scale format is more similar. We provide support for our framework in 14 studies.
Barasz, K., Kim, T., & Evangelidis, I. (2019). I Know Why You Voted for Trump: (Over)inferring Motives Based on Choice. Cognition, 188, 85–97.
Abstract
People often speculate about why others make the choices they do. This paper investigates how such inferences are formed as a function of what is chosen. Specifically, when observers encounter someone else’s choice (e.g., of political candidate), they use the chosen option’s attribute values (e.g., a candidate’s specific stance on a policy issue) to infer the importance of that attribute (e.g., the policy issue) to the decision-maker. Consequently, when a chosen option has an attribute whose value is extreme (e.g., an extreme policy stance), observers infer—sometimes incorrectly—that this attribute disproportionately motivated the decision-maker’s choice. Seven studies demonstrate how observers use an attribute’s value to infer its weight—the value-weight heuristic—and identify the role of perceived diagnosticity: more extreme attribute values give observers the subjective sense that they know more about a decision-maker’s preferences, and in turn, increase the attribute’s perceived importance. The paper explores how this heuristic can produce erroneous inferences and influence broader beliefs about decision-makers.
Evangelidis, I., & Levav, J. (2019). Process Utility and the Effect of Inaction Frames. Management Science, 65 (5), 2328–2341.
Abstract
We introduce a new type of utility that we call “process utility,” which pertains to individuals’ preference about how they want to obtain an outcome. We posit that decision makers derive utility not only from the outcome itself, but also from the process through which that outcome is obtained. We focus on two normatively equivalent processes for obtaining an outcome: action and inaction. We argue that inducing differences in how outcomes are obtained can lead to significant preference reversals. We examine process utility in binary choice where one outcome is predominantly preferred over the other. We find that when the frequently selected (“advantaged”) alternative is framed as an inaction, its choice share decreases, but that when the infrequently selected (“disadvantaged”) alternative is framed as an inaction, its choice share increases. Finally, we discuss potential moderators of our effects.
Evangelidis, I., Levav, J., & Simonson, I. (2018). The Asymmetric Impact of Context on Advantaged versus Disadvantaged Options. Journal of Marketing Research, 55 (2), 239–253.
Abstract
Despite substantial prior research regarding the effect of context on choices, uncertainty remains regarding when particular context effects will be observed. In this article, the authors advance a new perspective on context-dependent choices, according to which context effects are a function of the relative advantage of one option over another and of the different strategies that decision makers evoke when making a choice. They propose that context effects resulting from the addition of a third option to a two-option set are more frequently observed when the added option is relatively similar (adjacent) to the “disadvantaged” alternative (i.e., the lower-share option) in the set. The authors conduct a series of studies to analyze the occurrence of context effects and find support for predictions related to asymmetric dominance and extremeness aversion.
Evangelidis, I., & van Osselaer, S. (2018). Points of (Dis)parity: Expectation Disconfirmation from Common Attributes in Consumer Choice. Journal of Marketing Research, 55 (1), 1–13.
Abstract
Whereas many theories of decision making predict that presenting or not presenting common features of choice alternatives should not affect choice, in this research we show that common features can be a powerful driver of choice behavior. We conjecture that consumers often hold expectations about the features the choice alternatives have in common, and demonstrate that presenting (vs. omitting) a common feature increases the choice probability of the alternative that would have been expected to perform worse on the common feature. This effect occurs because performance on the common feature is judged not at face value, but relative to an expectation about which product should perform best on that feature. The effect obtains despite the fact that performance on the common feature is clearly the same when alternatives are presented side by side. Finally, we demonstrate four boundary conditions of our effect.
Evangelidis, I. (2017). The Role of Restraint Omission in Alcohol-Related Traffic Fatalities. Drug & Alcohol Dependence, 180, 423–426.
Abstract
Fatal traffic accidents affect thousands of people in the US alone every year. Alcohol consumption has been identified as a strong predictor of traffic fatalities. This result is hardly surprising as drivers who decide to consume alcohol and then drive are more likely to exhibit poor driving performance. In this paper, I argue that alcohol consumption can lead to traffic fatalities by increasing restraint omission.
Etkin, J., Evangelidis, I., & Aaker, J. (2015). Pressed for Time? Goal Conflict Shapes how Time is Perceived, Spent, and Valued. Journal of Marketing Research, 52 (3), 394–406.
Abstract
Consumers often feel pressed for time, but why? This research provides a novel answer to this question: subjective perceptions of goal conflict. We show that beyond the number of goals competing for their time, perceived conflict between goals makes consumers feel that they have less time. Five experiments demonstrate that perceiving greater conflict between goals makes people feel time constrained, driven by increased stress and anxiety. These effects, which generalize across a variety of goals and types of conflicts, impact how consumers spend time as well as how much they are willing to pay to save time. We identify two simple interventions that can help consumers mitigate goal conflict's negative effects: slow breathing and anxiety reappraisal. Together our findings shed light on what drives how consumers see, spend, and value their time.
Evangelidis, I., & Levav, J. (2013). Prominence versus Dominance: How Relationships between Alternatives Drive Decision Strategy and Choice. Journal of Marketing Research, 50 (6), 753–766.
Abstract
This article argues that the structure of a choice set can influence the extent to which consumers weight a given attribute. The results of seven experiments suggest that the relationship between options under consideration can influence preference ordering by shifting the decision strategy people adopt when constructing their preference. In decisions in which people afford greater importance to one attribute versus another, preference for an option that scores high on this prominent attribute may decrease when decoy options that are clearly better or worse than the focal options are inserted into the choice set. The authors posit that this effect arises because decision makers initially (and spontaneously) use dominance cues rather than prominence when evaluating options, and they continue to use this strategy even when it does not enable them to differentiate the alternatives under consideration. The authors moderate this effect by prompting respondents to consider prominence and by manipulating the order in which respondents evaluate options in the choice set. This article has theoretical implications for research on context effects, contingent decision behavior, and choice architecture as well as practical implications for product-line management.
Evangelidis, I., & Van den Bergh, B. (2013). The Number of Fatalities Drives Disaster Aid: Increasing Sensitivity to People in Need. Psychological Science, 24 (11), 2226–2234.
Abstract
In the studies reported here, an analysis of financial donations in response to natural disasters showed that the amount of money allocated for humanitarian aid depends on the number of fatalities but not on the number of survivors who are affected by the disaster (i.e., the actual beneficiaries of the aid). On the basis of the experimental evidence, we discuss the underlying cause and provide guidelines to increase sensitivity to people in need.