Research

In a series of ten preregistered experiments (N = 2043), we investigate the effect of outcome valence on judgments of probability, negligence, and culpability – a phenomenon sometimes labelled moral (and legal) luck. We found that harmful outcomes, when contrasted with neutral outcomes, lead to an increased perceived probability of harm ex post, and consequently, to a greater attribution of negligence and culpability. Rather than simply postulating hindsight bias (as is common), we employ a variety of empirical means to demonstrate that the outcome-driven asymmetry across perceived probabilities constitutes a systematic cognitive distortion. We then explore three distinct strategies to alleviate the hindsight bias and its downstream effects on mens rea and culpability ascriptions. Not all strategies are successful, but some prove very promising. They should, we argue, be considered in criminal jurisprudence, where distortions due to the hindsight bias are likely considerable and deeply disconcerting.

Legal and moral luck goes against the basic principle of criminal law that responsibility ascriptions are based on the mental state of the perpetrator, rather than merely the outcome of her action. If outcome should not play a decisive role in responsibility ascriptions, the attempt versus perpetration distinction becomes more difficult to justify. One potential justification is that we never know whether the attempter would not have resigned from pursuing her criminal intent even at the last moment. However, this paper argues that resigning from criminal intent and trying to stop the criminal outcome, which is called the renunciation defense, can be just as subject to outcome luck as the attempt versus perpetration distinction. And yet the availability of the renunciation defense in court is outcome dependent. I show with a series of experiments (N=479) that outcome dependence for the renunciation defense is perceived as unjust and discuss the implications for the renunciation defense as well as attempt versus perpetration distinction.

In many spheres, the law takes the legal concept of causation to correspond to the folk concept (the correspondence assumption). Courts, including the US Supreme Court, tend to insist on the “common understanding” and that which is “natural to say” (Burrage v. United States) when it comes to expressions relating to causation, and frequently refuse to clarify the expression to juries. As recent work in psychology and experimental philosophy has uncovered, lay attributions of causation are susceptible to a great number of unexpected factors, some of which seem rather peripheral to causation. One of those is the norm effect (Knobe & Fraser, 2008): Agents who, in acting as they do, break a salient norm, are more likely to be considered as having caused a certain consequence than when they do not violate a norm. According to some (e.g., Alicke, 1992) this constitutes a bias. According to others (e.g., Sytsma, 2021), the folk concept of causation is sensitive to normative factors, and there’s nothing wrong with that.

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In this paper, we explore the question whether the norm effect should be considered a bias from the legal perspective on the one hand, and from the psychological perspective on the other. To do this, we test whether norms which are nonpertinent to the consequences or outright silly also impact causation judgements. The data from two preregistered experiments (total N=593) clearly show they do. This, we argue, makes the bias interpretation plausible from the psychological perspective, and both plausible and problematic from the legal perspective. It also shows that the law should abstain from unreflectively assuming conceptual correspondence between legal and ordinary language concepts.

A cross-cultural survey experiment revealed a dominant tendency to rely on a rule’s letter over its spirit when deciding which behaviors violate the rule. This tendency varied markedly across (k = 15) countries, owing to variation in the impact of moral appraisals on judgments of rule violation. Compared with laypeople, legal experts were more inclined to disregard their moral evaluations of the acts altogether and consequently exhibited stronger textualist tendencies. Finally, we evaluated a plausible mechanism for the emergence of textualism: in a two-player coordination game, incentives to coordinate in the absence of communication reinforced participants’ adherence to rules’ literal meaning. Together, these studies (total n = 5,794) help clarify the origins and allure of textualism, especially in the law. Within heterogeneous communities in which members diverge in their moral appraisals involving a rule’s purpose, the rule’s literal meaning provides a clear focal point—an identifiable point of agreement enabling coordinated interpretation among citizens, lawmakers, and judges.

This paper presents a series of studies (total N=579) which demonstrate that folk judgments concerning the reasonableness of decisions and actions depend strongly on whether they engender positive or negative consequences. A particular decision is deemed more reasonable in retrospect when it produces beneficial consequences than when it produces harmful consequences, even if the situation in which the decision was taken and the epistemic circumstances of the agent are held fixed across conditions. This finding is worrisome for the law, where the reasonable person standard plays a prominent role. The legal concept of reasonableness is outcome-insensitive: whether the defendant acted in a reasonable fashion or not depends exclusively on her context of action, no matter how things play out. Folk judgments of reasonableness are thus inconsistent with the legal concept of reasonableness. Problematically, in common law jurisdictions, the decision whether a defendant’s behavior was reasonable or not is frequently (though not necessarily) delegated to a lay jury.

A growing body of literature has revealed ordinary causal judgement to be sensitive to normative factors, such that a norm violating agent is regarded more causal than their non-norm violating counterpart. The present paper aims to tease apart two competing explanations: the Responsibility View and the Bias View. The Bias View, but not the Responsibility View, predicts features peripheral to the agent’s responsibility to impact causal attributions. In a series of preregistered experiments, we present new evidence that the Norm Effect arises from such peripheral features, e.g., from nonpertinent or entirely silly norm violations. Further, we show that this effect is mediated neither by the agent’s foreknowledge or desire of the outcome, nor by its objective foreseeability: the Norm Effect arises even when participants judge the norm violating agent’s doing as equally foreseeable. We conclude by spelling out the legal implications. 

In this paper, I investigate: (1) to what extent do folk ascriptions of lying differ between casual and courtroom contexts? (2) to what extent does motive (reason) to lie influence ascriptions of trust, mental states, and lying judgments? (3) to what extent are lying judgments consistent with previous ascriptions of communicated content? Follow- ing the Supreme Court’s Bronston judgment, I expect: (1) averaged lying judgments to be similar in casual and courtroom contexts; (2) motive to lie to influence levels of trust, mental states ascriptions, and patterns of lying judgments; (3) retrospective judgments of lying, after being presented with the state of the world, to be incon- sistent with previous judgments of communicated content: participants hold the protagonist responsible for content she did not communicate. I performed a survey experiment on the Qualtrics platform. Participants were recruited through Amazon Mechanical Turk (N=630). I employed standard Likert scales and forced-choice questions. I found that: (1) average lying judgments are similar in casual and court- room contexts; (2) motive to lie decreases trust ascription and increases lying judg- ment; (3) judgments of lying are inconsistent with previous judgments of communi- cated content: participants hold the protagonist responsible for content they did not communicate (effect size of the difference d=.69). Perjury ascriptions are incon- sistent. The Supreme Court’s worries expressed in the Bronston judgment are well founded. This article helps reforming jury instructions in perjury cases.

In a series of ten preregistered experiments (N=2043), we investigate the effect of outcome valence on judgments of probability, negligence, and culpability – a phenomenon sometimes labelled moral (and legal) luck. We found that harmful outcomes, when contrasted with neutral outcomes, lead to increased perceived probability of harm ex post, and consequently to increased attribution of negligence and culpability. Rather than simply postulating a hindsight bias (as is common), we employ a variety of empirical means to demonstrate that the outcome-driven asymmetry across perceived probabilities constitutes a systematic cognitive distortion. We then explore three distinct strategies to alleviate the hindsight bias and its downstream effects on mens rea and culpability ascriptions. Not all are successful, but at least some prove promising. They should, we argue, be taken into consideration in criminal jurisprudence, where distortions due to the hindsight bias are likely considerable and deeply disconcerting.

At the height of the Covid-19 pandemic, frontline medical professionals at intensive care units around the world faced gruesome decisions about how to ration life-saving medical resources. These events provided a unique lens through which to understand how the public reasons about real-world dilemmas involving trade-offs between human lives. In three studies (total N=2298), we examined people’s moral attitudes toward the triage of acute coronavirus patients, and found elevated support for utilitarian triage policies. These utilitarian tendencies did not stem from period change in moral attitudes relative to pre-pandemic levels–but rather, from the heightened realism of triage dilemmas. Participants favoured utilitarian resolutions of critical care dilemmas when compared to structurally analogous, non-medical dilemmas–and such support was rooted in prosocial dispositions, including empathy and impartial beneficence. Finally, despite abundant evidence of political polarisation surrounding Covid-19, moral views about critical care triage differed modestly, if at all, between liberals and conservatives. Taken together, our findings highlight people’s robust support for utilitarian measures in the face of a global public health threat, and illustrate how the dominant methods in moral psychology (e.g. trolley cases) may deliver insights that do not generalise to real- world moral dilemmas.

The role of character evidence in court as a potential source of bias has been hotly debated, yet the empirical evidence on the effects character evidence might have on legal reasoning is scarce and has rendered mixed results. In this paper, we aim to (1) shed more light on the potentially biasing effect of character evidence, and (2) directly test whether jurors are more or less affected by character evidence than legal professionals. Across a range of preregistered experiments in different jurisdictions (UK, US, Australia, and a mixed sample), we consistently find that morally bad defendants are judged as acting more intentionally, knowingly, and recklessly than morally good defendants. We also consistently find higher perceived likelihood of failure judgments as well as higher blame and punishment attributions for morally bad defendants. Importantly, we found the same moral character effects among lay people and legal experts.

When two actors have the same mental state but one happens to harm another person (unlucky actor) and the other one does not (lucky actor), the latter elicits a milder moral judgement. To understand how this outcome effect would affect post-harm interactions between victims and perpetrators, we examined how the social role from which transgressions are perceived moderates the outcome effect, and how outcome effects on moral judgements transfer to agentic and communal interpersonal goals. Three vignette experiments (N = 950) revealed similar outcome effects on moral judgement across social roles. In contrast, outcome effects on agentic and communal goals var- ied by social role: victims exhibited the strongest outcome effects and perpetrators the weakest, with bystanders falling in between. Moral judgement did not mediate the effects of outcome severity on interpersonal goals. We discuss the possibility that out- come severity raises normative expectations regarding post-harm interactions that are unrelated to moral considerations.

There is a large literature exploring the effect of norms on the attribution of causation. Empirical research on this so-called “norm effect” has predominantly focused on two data points: A situation in which an agent violates a salient norm, and one in which there is no violation of a salient norm. Since the phenomenon is understood in binary terms (norm infraction vs. no norm infraction), most explanations thereof have the same structure. In this paper, we report several studies (total N=479) according to which perceived causation depends on the strength of the norm violated – whether strength is conceived in terms of the norm’s strictness, explicitness or associated punishment. Consequently, the norm effect, properly conceived, is not binary but graded in nature — the standard data points (norm violation vs. no norm violation) are but a special case of a broader phenomenon. This, we argue, puts pressure on many, if not most, of the current explanations of the norm effect on causal attributions.

While philosophers hold that it is patently absurd to blame robots or hold them morally responsible [1], a series of recent empirical studies suggest that people do ascribe blame to AI systems and robots in certain contexts [2]. This is disconcerting: Blame might be shifted from the owners, users or designers of AI systems to the systems themselves, leading to the diminished accountability of the responsible human agents [3]. In this paper, we explore one of the potential underlying reasons for robot blame, namely the folk's willingness to ascribe inculpating mental states or "mens rea" to robots. In a vignette-based experiment (N=513), we presented participants with a situation in which an agent knowingly runs the risk of bringing about substantial harm. We manipulated agent type (human v. group agent v. AI-driven robot) and outcome (neutral v. bad), and measured both moral judgment (wrongness of the action and blameworthiness of the agent) and mental states attributed to the agent (recklessness and the desire to inflict harm). We found that (i) judgments of wrongness and blame were relatively similar across agent types, possibly because (ii) attributions of mental states were, as suspected, similar across agent types. This raised the question - also explored in the experiment - whether people attribute knowledge and desire to robots in a merely metaphorical way (e.g., the robot "knew" rather than really knew). However, (iii), according to our data people were unwilling to downgrade to mens rea in a merely metaphorical sense when given the chance. Finally, (iv), we report a surprising and novel finding, which we call the inverse outcome effect on robot blame: People were less willing to blame artificial agents for bad outcomes than for neutral outcomes. This suggests that they are implicitly aware of the dangers of overattributing blame to robots when harm comes to pass, such as inappropriately letting the responsible human agent off the moral hook.

Recent research shows - somewhat astonishingly - that people are willing to ascribe moral blame to AI-driven systems when they cause harm [1]-[4]. In this paper, we explore the moral-psychological underpinnings of these findings. Our hypothesis was that the reason why people ascribe moral blame to AI systems is that they consider them capable of entertaining inculpating mental states (what is called mens rea in the law). To explore this hypothesis, we created a scenario in which an AI system runs a risk of poisoning people by using a novel type of fertilizer. Manipulating the computational (or quasi-cognitive) abilities of the AI system in a between-subjects design, we tested whether people's willingness to ascribe knowledge of a substantial risk of harm (i.e., recklessness) and blame to the AI system. Furthermore, we investigated whether the ascription of recklessness and blame to the AI system would influence the perceived blameworthiness of the system's user (or owner). In an experiment with 347 participants, we found (i) that people are willing to ascribe blame to AI systems in contexts of recklessness, (ii) that blame ascriptions depend strongly on the willingness to attribute recklessness and (iii) that the latter, in turn, depends on the perceived "cognitive" capacities of the system. Furthermore, our results suggest (iv) that the higher the computational sophistication of the AI system, the more blame is shifted from the human user to the AI system.

In this paper, we call for a new approach to the psychology of free will attribution. While past research in experimental philosophy and psychology has mostly been focused on reasoning- based judgment (“the courtroom approach”), we argue that like agency and mindedness, free will can also be experienced perceptually (“the perceptual approach”). We further propose a new model of free will attribution—the agency model—according to which the experience of free will is elicited by the perceptual cues that prompt the attribution of agency. Finally, developing new stimuli that fit the perceptual approach, we present some preliminary evidence in support of the agency model.

Standard research on the 'side-effect effect' or 'Knobe effect', has shown that foreseen harmful side effects are judged intentional and helpful side effects (all other things remaining equal) are judged unintentional. Research conducted by Kneer & Bourgeois-Gironde (2017), however, suggests that empirical research on the Knobe effect might have inappropriately focused but on two data points out of many. The scholars found that people’s ascriptions of intentionality are susceptible not only to the Knobe effect but to a ‘severity effect’: the more harmful the side effect, the more inclined people are to say that it was intentionally brought about. Rather than being of binary nature, the relation between outcomes and intentionality ascriptions appears to be a matter of degrees. Problematically, however, the research on the severity effect suffers from a shortcoming: focus has been placed on intentionality ascriptions for graded harmful outcomes; graded helpful outcomes have not been tested. To address the former lacuna and provide a clearer understanding of the relation between outcomes and intentionality ascriptions, we conducted a study exploring attributions of intentionality (and knowledge) across a range of different outcomes: very bad, somewhat bad, neutral, somewhat good and very good. The results of two preregistered experiments suggest that the relation between intentionality ascriptions and outcomes is indeed of graded nature and that outcome valence plays a role in defining the strength of such relation. The findings, we further argue, provide particular support to blame-driven bias accounts of the phenomenon underlying the Knobe effect.

There is an ever-growing body of psychological literature that details the influence of norms on ordinary causal judgement. The practical relevance of this line of research culminates in the law, as both norm-violations and causal judgements constitute the bedrock upon which criminal and tort cases are built. Two accounts give competing explanations of this phenomenon. On the bias view, participants blame the norm-violating agent, thereby forming a negative picture of her and, in an act of backwards-rationalisation, labelling her as more causal. On the responsibility view, the ordinary concept of causation is simply normatively valenced, and participants rightfully label the norm-violating agent as more causal. In our present paper, we show that the violation of norms which do not play into moral responsibility—such as entirely silly norms—nevertheless have a pronounced impact on causal ascription, thus buttressing the bias view. From the perspective of the law, these findings raise a multitude of worries.

An affect-driven information processing might explain why professional judges are sensitive to the outcome severity in their ascription of intention (Kneer & Bourgeois-Gironde, 2017), although culpable mental states (mentes reae) should be judged independently from the forbidden act (actus reus) and its outcome. Similar processes could occur if judges or juries get confronted with other affect-laden information, like the suspect's moral character, which should neither be considered in ascribing mens rea (cf. e.g., Nadler, 2012). We report the first empirical investigation into the affective-mediated ascription of mens rea (recklessness and negligence) made by legal experts. We conducted two studies and found that laypeople and legal experts reported stronger negative affect, ascribed more blame to the suspect, and were more willing to ascribe inculpating states of mind if the suspect had a bad moral character than if the suspect had a good moral character. Interestingly, after evaluating further evidence, the character had bigger effects on the ascription of blame and mens rea in the study with experts than in the study with laypeople, although experts report lower levels of initial blame and negative affect. Furthermore, we found significant indirect effects for character via negative affect on all dependent variables in the sample with laypeople, but not in the expert sample. 

According to Anscombe, acting intentionally entails knowledge in action. This thesis has been near-universally rejected due to a well-known counterexample by Davidson: a man intending to make ten legible carbon copies might not believe with confidence, and hence not know, that he will succeed. If he does, however, his action surely counts as intentional. Damaging as it seems, an even more powerful objection can be levelled against Anscombe: while acting, there is as yet no fact of the matter as to whether the agent will succeed. Since his belief that he will is not yet true while his action is in progress, he cannot possibly know that he is indeed bringing about the intended goal. Knowledge in action is not only unnecessary for intentional action, it seems, but-at least as regards success-bound types of action-impossible to attain in the first place.

Despite pervasive variation in the content of laws, legal theorists and anthropologists have often argued that all laws share certain abstract features and even speculated that law may be a human universal. In the present report, we contribute cross-cultural data to this debate: Are there essential features of law? Participants in ten different countries (N = 2844) were asked whether there could be laws that violate certain procedural principles (e.g., laws applied retrospectively or unintelligible laws), and also whether there are any such laws—in a between-subjects design. Confirming our pre-registered prediction, people reported that such laws cannot exist, but also (paradoxically) that there are such laws. These results document a tendency toward legal essentialism across cultures and languages: universal beliefs about the nature of law which defy people's conception of how legal systems function in practice.

When two actors have the same mental state but one happens to harm another person (unlucky actor) and the other one does not (lucky actor), the latter elicits a milder moral judgement. To understand how this outcome effect would affect post-harm interactions between victims and perpetrators, we examined how the social role from which transgressions are perceived moderates the outcome effect, and how outcome effects on moral judgements transfer to agentic and communal interpersonal goals. Three vignette experiments (N = 950) revealed similar outcome effects on moral judgement across social roles. In contrast, outcome effects on agentic and communal goals varied by social role: victims exhibited the strongest outcome effects and perpetrators the weakest, with bystanders falling in between. Moral judgement did not mediate the effects of outcome severity on interpersonal goals. We discuss the possibility that outcome severity raises normative expectations regarding post-harm interactions that are unrelated to moral considerations.

Standard research on the 'side-effect effect' or 'Knobe effect', has shown that foreseen harmful side effects are judged intentional and helpful side effects (all other things remaining equal) are judged unintentional. Research conducted by Kneer & Bourgeois-Gironde (2017), however, suggests that empirical research on the Knobe effect might have inappropriately focused but on two data points out of many. The scholars found that people’s ascriptions of intentionality are susceptible not only to the Knobe effect but to a ‘severity effect’: the more harmful the side effect, the more inclined people are to say that it was intentionally brought about. Rather than being of binary nature, the relation between outcomes and intentionality ascriptions appears to be a matter of degrees. Problematically, however, the research on the severity effect suffers from a shortcoming: focus has been placed on intentionality ascriptions for graded harmful outcomes; graded helpful outcomes have not been tested. To address the former lacuna and provide a clearer understanding of the relation between outcomes and intentionality ascriptions, we conducted a study exploring attributions of intentionality (and knowledge) across a range of different outcomes: very bad, somewhat bad, neutral, somewhat good and very good. The results of two preregistered experiments suggest that the relation between intentionality ascriptions and outcomes is indeed of graded nature and that outcome valence plays a role in defining the strength of such relation. The findings, we further argue, provide particular support to blame-driven bias accounts of the phenomenon underlying the Knobe effect.

The mental state of the perpetrator is decisive for criminal legal responsibility. However, there is one exception, inconsistent with the remaining rules. Imagine that John lights a long fuse in order to burn his enemy’s house. After a short while, John has second thoughts. Consequently, he tries to stamp out the fuse. There are two possible outcomes. The first outcome is lucky: John stamps out the fuse easily and the enemy survives. However, it could also be that a strong wind prevents John from stamping out the fuse. As a result, John’s enemy dies anyway. In both cases, the lucky and the unlucky one, John has the same quality of the will: he initially intends a criminal outcome, yet later, on second thoughts, desists from his criminal intent and does everything he can to prevent the criminal outcome. While his actions are intentional, the outcome is accidental as it is not fully under John’s control – it is subject to causal luck. In many legal systems (except for ex. Poland as well as the states of Arizona and Hawaii), the lucky John commits an attempt and can receive a substantial mitigation of punishment on the basis of the renunciation defense, while the unlucky John gets fully punished. Yet is it fair to hold an agent responsible for outcomes not under the agent’s control? Since in common law systems responsibility decisions are taken by a jury, consulting folk intuitions is necessary to answer the question. In a series of experiments (total N = 479), we investigate folk intuitions concerning John’s case. The influence of outcome on responsibility ascriptions is mitigated in the within subjects design as compared to the between subjects design (effect size of the difference in between subjects d = .87; versus effect in within subjects d = .35). We conclude that reflective folk intuitions are Kantian with respect to the renunciation case and thus the legal rules should be reformulated consistently with the remaining rules on legal responsibility, as fairness intuitions align with the Kantian view.

Moral philosophers and psychologists often assume that people judge morally lucky and morally unlucky agents differently, an assumption that stands at the heart of the Puzzle of Moral Luck. We examine whether the asymmetry is found for reflective intuitions regarding wrongness, blame, permissibility, and punishment judg- ments, whether people’s concrete, case-based judgments align with their explicit, abstract principles regarding moral luck, and what psychological mechanisms might drive the effect. Our experiments produce three findings: First, in within-subjects experiments favorable to reflective deliberation, the vast majority of people judge a lucky and an unlucky agent as equally blameworthy, and their actions as equally wrong and permissible. The philosophical Puzzle of Moral Luck, and the challenge to the very possibility of systematic ethics it is frequently taken to engender, thus simply do not arise. Second, punishment judgments are significantly more outcome- dependent than wrongness, blame, and permissibility judgments. While this constitutes evidence in favor of current Dual Process Theories of moral judgment, the latter need to be qualified: punishment and blame judgments do not seem to be driven by the same process, as is commonly argued in the literature. Third, in between-subjects experiments, outcome has an effect on all four types of moral judgments. This effect is mediated by negligence ascriptions and can ultimately be explained as due to differing probability ascriptions across cases.

This article explores whether perspective taking has an impact on the ascription of epistemic states. To do so, a new method is introduced which incites participants to imagine themselves in the position of the protagonist of a short vignette and to judge from her perspective. In a series of experiments (total N=1980), perspective proves to have a significant impact on belief ascriptions, but not on knowledge ascriptions. For belief, perspective is further found to moderate the epistemic side-effect effect significantly. It is hypothesized that the surprising findings are driven by the special epistemic authority we enjoy in assessing our own belief states, which does not extend to the assessment of our own knowledge states.

A coherent practice of mens rea (‘guilty mind’) ascription in criminal law presupposes a concept of mens rea which is insensitive to the moral valence of an action’s outcome. For instance, an assessment of whether an agent harmed another person intentionally should be unaffected by the severity of harm done. Ascriptions of intentionality made by laypeople, however, are subject to a strong outcome bias. As demonstrated by the Knobe effect, a knowingly incurred negative side effect is standardly judged intentional, whereas a positive side effect is not. We report the first empirical investigation into intentionality ascriptions made by professional judges, which finds (i) that professionals are sensitive to the moral valence of outcome type, and (ii) that the worse the outcome, the higher the propensity to ascribe intentionality. The data shows the intentionality ascriptions of professional judges to be inconsistent with the concept of mens rea supposedly at the foundation of criminal law.