Publications
Self-image, self-signaling, and the socially adapted mind (Preprint, Publication)
Recent work in behavioral economics has suggested that individuals derive utility from the beliefs that they hold. The objective of this paper is to reevaluate the idea that (i) individuals care about their self-image and (ii) individuals self-signal. I first argue that the desired self-image is best seen as the desired reputation. Then, I defend the idea that what appears to be self-signaling in the laboratory reflects the workings of a psychology well-adapted to the social incentives of everyday life, which spills over when individuals find themselves in new, contrived environments.
Preprints
Why are lies small? (with D. Nettle) (Link)
Deception is common, yet lies are typically small and not easily spotted. The dominant explanations for why this is the case are psychological in nature, such that small lies are thought to allow individuals to maintain their self-concept or that individuals have a general preference for truth-telling. In this paper, we suggest that lies are typically small because small lies allow individuals to retrieve benefits associated with lying while preventing punishment from interaction partners. We present two game-theoretic models in which agents are incentivized to misreport private information. In a two-player game, we show that the equilibrium size of the lie is predicted to be smaller when the reputational costs of lying are larger, and smaller when the state of the world is more observable. In a three-player game, we show that lies can remain stable in group settings provided that the equilibrium size of the lie is small enough, so that the sender retains plausible deniability about lying. A unique and central prediction of our models is that biased self-presentation will be modulated by the degree of observability of the trait. We review the empirical literature on positive illusions, and argue that the findings support this prediction. We propose that the aversion to lying observed in laboratory experiments reflects the workings of a psychology well-adapted to the incentive structure of natural environments and suggest that models of human social behavior should focus on capturing relevant parameters from such environments.
Psychological utility functions for income are S-shaped: evidence from UK adults (with D. Nettle) (Link)
Do people’s psychological valuations of income obey everywhere-diminishing marginal utility, or are they S-shaped, as proposed by the Desperation Threshold Model and found in some prior research? We ran a pre-registered study with UK adults (N = 150, Prolific) where participants rated the value to them of 41 different monthly incomes (£1–£8000; random order). Comparing the fit of different classes of function, the most frequent best fit was sigmoid (59% of respondents; quadratic 37%; linear 5%). Generalized Additive Models corroborated the S-shape: the mean first derivative rose at low incomes and fell at higher incomes, while the mean second derivative was positive at low incomes and negative thereafter, with the inflection around £1,600/month. Exact question wording did not appear to affect the shape. The midpoint of the S-shape increased with respondents’ own income and the typical income of people they know. Thus, in this population, directly elicited psychological utility functions for income appear to be S-shaped, consistent with earlier findings and the Desperation Threshold Model: marginal utility increases up to a basic-needs threshold and decreases beyond it. Because the inflection lies at an income level actually experience by millions of Britons, these findings have potentially important implications for understanding real-world behaviour.
Living on the edge: investigating experiences of poverty through the lens of the Desperation Threshold Model (with L. Carbuccia, Z. Makine and D. Nettle) (Link)
The Desperation Threshold Model (DTM) seeks to explain conflicting findings about the risk propensity of people living in poverty. It makes assumptions about their experiences: that they have a conception of basic needs, that their ability to meet these motivates their decisions, and that they modulate risky decisions depending on their ability to do so. The realism of these modeling assumptions has not yet been investigated. To start filling this gap, we investigated experiences of poverty through the lens of the DTM, using two complementary approaches: a pre-registered online survey with British participants (n = 300) and semi-structured qualitative interviews with very low-income individuals in France (n = 14). Our results imply that basic needs have both a context-general component and context-specific elaborations. Furthermore, participants often relied on social and institutional resources when experiencing financial adversity, indicating that only measuring personal income or wealth might not accurately capture the resources available to people. With respect to the DTM’s main predictions, most individuals close to—but still above—the desperation threshold exhibited caution and took a safety-first approach, consistent with risk-averse behavior. Risky or antisocial behaviors (e.g., cheating, stealing) emerged only in rare instances of severe financial hardship and complete lack of external support. These results suggest that the DTM’s main assumptions are empirically grounded but that they need to be qualified in specific ways. They also suggest that abstract models like the DTM can capture something about the experience of people living in conditions of poverty.
An evolutionary perspective on social preferences (Link)
In this paper, I argue that the theory of social evolution has the necessary scope and power to provide a useful theoretical framework for human social preferences. Social evolution theory applies to any social interaction and makes sharp predictions about the kinds of social traits that can be observed in the population. It illuminates the function of our social emotions, which are context-dependent, endogenous mechanisms that modulate our social relationships with others. I discuss two mechanisms that underlie the wide variation in the expression of social preferences: social norms (or institutions) and local ecology. The wealth of findings on human social preferences supports their context-dependent nature and prompts us to investigate the incentives underlying their expression.