I propose a framework of competing motivations in which different motives to exert effort can interfere with one another. Consequently, combining a strong incentive with a weaker one may be less motivating than offering the strong incentive alone. I test this hypothesis in three pre-registered experiments on Amazon MTurk via CloudResearch (N = 3,412). In the first study, participants completed real-effort tasks for monetary rewards, charitable rewards, or both; those working solely for money completed 23 percent more tasks than participants offered the same monetary reward combined with a charitable incentive. In the second study, participants worked for monetary rewards, a lottery reward, or both. While increasing the monetary piece rate raised effort, combining money with a lottery reward did not. The third study isolates the weaker incentives previously paired with money and shows that both the charity and lottery rewards independently increased effort relative to a no-incentive control. These findings support the competing motivations framework and challenge the assumption that motivations from different incentives combine additively.

We investigate the leading motivations for indirect reciprocity by experimentally studying the role of type-based, intentions-based, and outcome-based preferences. We design a novel experimental setting in which participants can help other participants under varying probability of being seen by third parties. Those third-party observers can then reward participants based on both their history of helpful behavior and the observability of that behavior. Because good deeds done in public are often strategically motivated to build reputation, while only truly altruistic people help in private, we can identify whether indirect reciprocity is directed towards good deeds or good people. We find that indirect reciprocity towards an individual is influenced by their previous attempts to be helpful and their impact on others, but is surprisingly unaffected by the authenticity of past benevolent actions. That is, good deeds are rewarded regardless of whether these actions reflect true altruism or are likely a strategic play to encourage future reciprocal kindness. We discuss implications for theories of indirect reciprocity and sustained cooperation in large groups.

When interacting with someone, their prior behavior towards us and others comprise their reputation, affecting our willingness to reciprocate. Yet, most research on reciprocity has largely examined direct and indirect reciprocity in isolation. We address this gap with a large-scale online experiment in which Reciprocators observed two one-shot decisions by a matched Helper—one affecting themselves and one affecting an anonymous third party—and then chose whether to help that same Helper. By controlling for the distribution of monetary payoffs and the Helper’s expectation of reciprocation, our design cleanly isolates the influence of direct versus indirect reciprocity when both are present. We find that although both forms of interaction drive reciprocation, direct reciprocity carries roughly twice as much weight as indirect reciprocity. These results cannot be fully explained by any existing model of reciprocity, underscoring the need for an integrated framework to understand reciprocal behavior in broader contexts. 

This field experiment investigates the effect of volunteering on future donation behaviour, aiming to understand if volunteering and donating are substitutes or complements.

I investigate the interplay between the inherent cost of a prosocial activity and the feelings of personal satisfaction (often termed "warm glow") that arise from engaging in such behaviours. Using a 2×2 experimental design, participants are divided into groups working either 'for themselves' or 'for charity', undergoing tasks that are either 'easy' or 'hard'. The study is designed to test the hypothesis that participants working for charity will experience greater warm glow when they work on more difficult tasks.