Ulrike Hahn

Ulrike Hahn
Birkbeck, University of London · Department of Psychological Sciences

About

210
Publications
79,503
Reads
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4,542
Citations
Introduction
Currently thinking a lot about testimony - how we gain knowledge from others, and how that interacts with the social networks we inhabit
Additional affiliations
September 1998 - July 2012
Cardiff University
Position
  • Academic

Publications

Publications (210)
Article
Full-text available
Received academic wisdom holds that human judgment is characterized by unrealistic optimism, the tendency to underestimate the likelihood of negative events and overestimate the likelihood of positive events. With recent questions being raised over the degree to which the majority of this research genuinely demonstrates optimism, attention to possi...
Article
Full-text available
A robust finding in social psychology is that people judge negative events as less likely to happen to themselves than to the average person, a behavior interpreted as showing that people are "unrealistically optimistic" in their judgments of risk concerning future life events. However, we demonstrate how unbiased responses can result in data patte...
Article
Three experiments provide evidence that the perceived similarity between two images is systematically affected by the inherent direction of a transformation that links the two. Participants were shown short animations morphing one object into another from the same basic category. They were then asked to make directional similarity judgments ("How s...
Article
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Classical studies suggest that high-level cognitive decisions (e.g., choosing between financial options) are suboptimal. In contrast, low-level decisions (e.g., choosing where to put your feet on a rocky ridge) appear near-optimal: the perception-cognition gap. Moreover, in classical tasks, people appear to put too much weight on unlikely events. I...
Article
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Classical informal reasoning "fallacies," for example, begging the question or arguing from ignorance, while ubiquitous in everyday argumentation, have been subject to little systematic investigation in cognitive psychology. In this article it is argued that these "fallacies" provide a rich taxonomy of argument forms that can be differentially stro...
Article
Base rate neglect refers to people's apparent tendency to underweight or even ignore base rate information when estimating posterior probabilities for events, such as the probability that a person with a positive cancer-test outcome actually does have cancer. While often replicated, almost all evidence for the phenomenon comes from studies that use...
Preprint
Full-text available
Providing an explanation is a communicative act. It includes an explainee, a person who is receiving an explanation, and an explainer, a person (or sometimes a machine) who provides an explanation. The majority of research on explanation has focused on how explanations alter explainees’ beliefs. However, one general feature of communicative acts is...
Preprint
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Counterfactual (CF) explanations have been employed as one of the modes of explainability in explainable AI-both to increase the transparency of AI systems and to provide recourse. Cognitive science and psychology, however, have pointed out that people regularly use CFs to express causal relationships. Most AI systems are only able to capture assoc...
Preprint
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The idea that objects can be represented within multi-dimensional ‘cognitive spaces’ remains popular within psychology and neuroscience, and yet the restrictive topology of such spaces is seldom considered. Here, we show that it is possible, even within a simple set of items, to break such models by imposing neighbourhood relations that are incompa...
Preprint
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How we judge the similarity between objects in the world is connected ultimately to how we represent those objects. It has been argued extensively that object representations in humans are ‘structured’ in nature, meaning that both individual features and the relations between them can influence similarity. In contrast, popular models of comparative...
Article
Consideration of collectives raises important questions about human rationality. This has long been known for questions about preferences, but it holds also with respect to beliefs. For one, there are contexts (such as voting) where we might care as much, or more, about the rationality of a collective than the rationality of the individuals it comp...
Article
We explore the common attributes of political conflicts in which scientific findings have a central role, using the COVID-19 pandemic as a case study, but also drawing on long-standing conflicts over climate change and vaccinations. We analyze situations in which the systematic spread of disinformation or conspiracy theories undermines public trust...
Article
How people update their beliefs when faced with new information is integral to everyday life. A sizeable body of literature suggests that people's belief updating is optimistically biased, such that their beliefs are updated more in response to good news than bad news. However, recent research demonstrates that findings previously interpreted as ev...
Article
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The ubiquity of social media use and the digital data traces it produces has triggered a potential methodological shift in the psychological sciences away from traditional, laboratory-based experimentation. The hope is that, by using computational social science methods to analyse large-scale observational data from social media, human behaviour ca...
Article
Indicative conditionals—that is, sentences typically, though not exclusively, of the form “If p, (then) q,”—belong to the most puzzling phenomena of language. One of the puzzles that has recently attracted attention of psychologists of reasoning stems from the fact that on the majority of accounts of indicative conditionals, “If p, (then) q” can be...
Article
Full-text available
The paper introduces, compares and contrasts formal models of source reliability proposed in the epistemology literature, in particular the prominent models of Bovens and Hartmann (2003) and Olsson (2011). All are Bayesian models seeking to provide normative guidance, yet they differ subtly in assumptions and resulting behavior. Models are evaluate...
Article
Full-text available
This paper explores ‘reasonable doubt’ as an enlightening notion to think of reasoning and decision-making generally, beyond the judicial domain. The paper starts from a decision-theoretic understanding of the notion, whereby it can be defined in terms of degrees of belief and a probabilistic confirmation threshold for action. It then highlights so...
Conference Paper
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Many collective decision-making contexts involve communication among group members. Sometimes this communication helps the collective reach an accurate decision because it allows individuals to gain otherwise unknown information from their peers, but sometimes this communication gives rise to detrimental social influence or “groupthink." Whether co...
Chapter
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As AI systems come to permeate human society, there is an increasing need for such systems to explain their actions, conclusions, or decisions. This is presently fuelling a surge in interest in machine-generated explanation in the field of explainable AI. In this chapter, we will consider work on explanations in areas ranging from AI to philosophy,...
Article
Full-text available
In many complex, real‐world situations, problem solving and decision making require effective reasoning about causation and uncertainty. However, human reasoning in these cases is prone to confusion and error. Bayesian networks (BNs) are an artificial intelligence technology that models uncertain situations, supporting better probabilistic and caus...
Preprint
Given the need for a rapid and supposed critical response from behavioural sciences during times of crisis, this study aimed to track the development of COVID-19 psychology-related preprints. We tracked the first 211 COVID related preprints on the repository PsyArXiv. Specifically, we tracked who was submitting preprints, what the preprints were in...
Preprint
In this paper, the fourth in a series of white papers, we provide a summary of the discussions and future directions that came from the topical meeting that focused on model construction with social media data. A particularly interesting aspect of this meeting was, in our view, discussion of the different disciplines’ requirements and approaches to...
Preprint
Full-text available
Base rate neglect refers to people's apparent tendency to underweight or even ignore base rate information when estimating posterior probabilities for events, such as the probability that a person with a positive cancer-test outcome actually does have cancer. While many studies have replicated the effect, there has been little variation in the stru...
Article
Most of the claims we encounter in real life can be assigned some degree of plausibility, even if they are new to us. On Gilbert's (1991) influential account of belief formation, whereby understanding a sentence implies representing it as true, all new propositions are initially accepted, before any assessment of their veracity. As a result, plausi...
Article
Full-text available
A longstanding question is the extent to which "reasonable doubt" may be expressed simply in terms of a threshold degree of belief. In this context, we examine the extent to which learning about possible alternatives may alter one's beliefs about a target hypothesis, even when no new "evidence" linking them to the hypothesis is acquired. Imagine th...
Article
Whether assessing the accuracy of expert forecasting, the pros and cons of group communication, or the value of evidence in diagnostic or predictive reasoning, dependencies between experts, group members, or evidence have traditionally been seen as a form of redundancy. We demonstrate that this conception of dependence conflates the structure of a...
Article
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Conditionals and conditional reasoning have been a long-standing focus of research across a number of disciplines, ranging from psychology through linguistics to philosophy. But almost no work has concerned itself with the question of how hearing or reading a conditional changes our beliefs. Given that we acquire much—perhaps most—of what we believ...
Article
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In reasoning about situations in which several causes lead to a common effect, a much studied and yet still not well-understood inference is that of explaining away. Assuming that the causes contribute independently to the effect, if we learn that the effect is present, then this increases the probability that one or more of the causes are present....
Article
In this article, we explore how people revise their belief in a hypothesis and the reliability of sources in circumstances where those sources are either independent or are partially dependent because of their shared, common background. Specifically, we examine people's revision of perceived source reliability by comparison with a formal model of r...
Article
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Bayesian reasoning and decision making is widely considered normative because it minimizes prediction error in a coherent way. However, it is often difficult to apply Bayesian principles to complex real world problems, which typically have many unknowns and interconnected variables. Bayesian network modeling techniques make it possible to model suc...
Article
Full-text available
Our beliefs and opinions are shaped by others, making our social networks crucial in determining what we believe to be true. Sometimes this is for the good because our peers help us form a more accurate opinion. Sometimes it is for the worse because we are led astray. In this context, we address via agent-based computer simulations the extent to wh...
Preprint
Full-text available
The present crisis demands an all-out response if it is to be mastered with minimal damage. This means we, as the behavioural science community, need to think about how we can adapt to best support evidence-based policy in a rapidly changing, high-stakes environment. This piece is an attempt to initiate this process. The ‘recommendations’ made are...
Preprint
In many complex, real-world situations, problem solving and decision making require effective reasoning about causation and uncertainty. However, human reasoning in these cases is prone to confusion and error. Bayesian networks (BNs) are an artificial intelligence technology that models uncertain situations, supporting probabilistic and causal reas...
Preprint
Full-text available
In many complex, real-world situations, problem solving and decision making require effective reasoning about causation and uncertainty. However, human reasoning in these cases is prone to confusion and error. Bayesian networks (BNs) are an artificial intelligence technology that models uncertain situations, supporting probabilistic and causal reas...
Article
The idea of resolving dispute through the exchange of arguments and reasons has been central to society for millennia. We exchange arguments as a way of getting at the truth in contexts as diverse as science, the court room, and our everyday lives. In democracies, political decisions should be negotiated through argument, not deception, or even wor...
Preprint
The paper introduces, compares and contrasts formal models of source reliability proposed in the epistemology literature, in particular the prominent models of Bovens and Hartmann (2003) and Olsson (2011). All are Bayesian models seeking to provide normative guidance, yet they differ subtly in assumptions and resulting behavior. Models are evaluate...
Article
Conditionals pervade every aspect of our thinking, from the mundane and everyday such as ‘if you eat too much cheese, you will have nightmares’ to the most fundamental concerns as in ‘if global warming isn’t halted, sea levels will rise dramatically’. Many decades of research have focussed on the semantics of conditionals and how people reason from...
Preprint
Full-text available
We start with the distinction of outcome- and belief-based Bayesian models of the sequential update of agents' beliefs and subjective reliability of sources (trust). We then focus on discussing the influential Bayesian model of belief-based trust update by Eric Olsson, which models dichotomic events and explicitly represents anti-reliability. After...
Article
Full-text available
In social-dilemma situations (e.g., public-good games), people may pursue their local self-interests, thereby lowering the overall payoff of their group and, paradoxically, even their individual payoffs as a result. Likewise, in inner-individual dilemmas, even without conflict of interest between persons, people may pursue local goals at the expens...
Article
We gain much of our knowledge from other people. Because people are fallible-they lie, mislead, and are mistaken-it seems essential to monitor their claims and their reliability as sources of information. An intuitive way to do this is to draw on our expectations about claims and sources: to perform expectation-based updating (Hahn, Merdes, & von S...
Article
We gain much of our knowledge from other people. Since people are fallible - they lie, mislead, and are mistaken - it seems essential to monitor their claims and their reliability as sources of information. An intuitive way to do this is to draw on our expectations about claims and sources: to perform expectation-based updating (Hahn, Merdes, & von...
Conference Paper
Full-text available
Social dilemmas conceptually suggest distinguishing direct individual and group-level effects (also involving indirect effects on others). Furthermore, the success of organizations appears to rely on identifying not only individual excellence but positive impact on others as well. In ‘Two-Level Personnel Evaluation Tasks’ (T-PETs) participants as h...
Conference Paper
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Sequential testimonies where more or less reliable sources argue about an issue are central to public debates. Often, the majority of sources may argue that a hypothesis is true while a minority dissenter may claim the opposite (e.g. scientists and lobbyists in the climate change debate). In this paper, we show that people are sensitive to source r...
Conference Paper
Full-text available
People increasingly turn to online social networks for information and debate. This means that the structures and properties of these networks, and the information they propagate, play crucial roles in the development of social beliefs, attitudes, and morals. Recently, research has shown that the presence of specific language drives the diffusion o...
Conference Paper
Full-text available
We start with the distinction of outcome-and belief-based Bayesian models of the sequential update of agents' beliefs and subjective reliability of sources (trust). We then focus on discussing the influential Bayesian model of belief-based trust update by Eric Olsson, which models dichotomic events and explicitly represents anti-reliability. After...
Article
Full-text available
With the advent of social media, the last decade has seen profound changes to the way people receive information. This has fueled a debate about the ways (if any) changes to the nature of our information networks might be affecting voters’ beliefs about the world, voting results, and, ultimately, democracy. At the same time, much discussion in the...
Article
Full-text available
In real world contexts of reasoning about evidence, that evidence frequently arrives sequentially. Moreover, we often cannot anticipate in advance what kinds of evidence we will eventually encounter. This raises the question of what we do to our existing models when we encounter new variables to consider. The standard normative framework for probab...
Article
Full-text available
Suppose that two competing norms, N1 and N2, can be identified such that a given person’s response can be interpreted as correct according to N1 but incorrect according to N2. Which of these two norms, if any, should one use to interpret such a response? In this paper we seek to address this fundamental problem by studying individual variation in t...
Article
Full-text available
In this paper, new evidence is presented for the assumption that the reason-relation reading of indicative conditionals ('if A, then C') reflects a conventional implicature. In four experiments, it is investigated whether relevance effects found for the probability assessment of indicative conditionals (Skovgaard-Olsen, Singmann, and Klauer, 2016a)...
Chapter
We frequently communicate risk and uncertainty with verbal probability expressions (VPE): expressions such as "unlikely", "possible", and "likely". Such expressions are, it is believed, so vaguely understood that there is an "illusion of communication": speaker and hearer believe that they understand each other but, in fact, do not. In this chapter...
Article
Full-text available
This paper examines the basic question of how we can come to form accurate beliefs about the world when we do not fully know how good or bad our evidence is. Here we show, using simulations with otherwise optimal agents, the cost of misjudging the quality of our evidence, and compare different strategies for correctly estimating that quality, such...
Article
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„… Um unsere Kernaufgabe – Fortschritt durch Wissen – erfüllen zu können, brauchen Wissenschaftler jetzt zwei Arten von Kommunikation: zum einen die mit unseren Wissenschaftskollegen, zum anderen die schwierigere, aber umso wichtigere, Kommunikation mit der breiten Öffentlichkeit. Als Wissenschaftlerinnen und Wissenschaftler muss es uns gelingen, e...
Article
“… Achieving our core mission, namely progress through knowledge, now requires two kinds of communication: one to our scientific peers, but another, more fraught yet critical, to the broader public. As scientists, we need to forge a better relationship between the world of research and the general public …” Read more in the Guest Editorial by K. Bo...
Conference Paper
Full-text available
With the advent of social media, the last decade has seen profound changes to the way people receive information. This has fueled debate about the ways (if any) changes to the nature of our information networks might be affecting voters' beliefs about the world, voting results, and, ultimately, democracy. At the same time, much discussion in the pu...
Article
Understanding the scientific consensus on anthropogenic climate change has been dubbed a ‘gateway belief’ to engaging people in sustainable behaviour. We consider the question of how the impact of a consensus communication can be maximised. Firstly, the credibility of the communicator should be maximised. One way of achieving this is to present the...
Article
Full-text available
Much of what we believe we know, we know through the testimony of others (Coady, 1992). While there has been long-standing evidence that people are sensitive to the characteristics of the sources of testimony, for example in the context of persuasion, researchers have only recently begun to explore the wider implications of source reliability consi...
Conference Paper
Full-text available
Testimony is a fundamental feature of human life: typically, we receive testimonial evidence from others multiple times each day. Often, we have more than one source attesting to a particular claim. This paper examines the way people integrate testimonial evidence from multiple sources. We find evidence that participants deviate substantially from...
Article
Full-text available
Human randomness perception is commonly described as biased. This is because when generating random sequences humans tend to systematically under- and overrepresent certain subsequences relative to the number expected from an unbiased random process. In a purely theoretical analysis we have previously suggested that common misperceptions of randomn...
Chapter
Full-text available
Value instantiations – exemplifiers of an abstract or general category – are a new issue in human value research. Experiments have recently highlighted the important role of value instantiations in bridging the gap between abstract values and specific actions. In this chapter, we describe the general role of category instantiations in psychology, d...
Conference Paper
Full-text available
Indicative conditionals, that is sentences of the form "If p, then q," belong to the most puzzling phenomena of language. On the majority of accounts of indicative conditionals, the truth of p and q suffices for "If p, then q" to be true or highly acceptable. Yet, many conditionals with true clauses, even if there is a meaningful connection between...
Conference Paper
Full-text available
In this manuscript we study individual variation in the interpretation of conditionals by establishing individual profiles of the participants based on their behavioral responses and reflective attitudes. To investigate the participants' reflective attitudes we introduce a new experimental paradigm called the Scorekeeping Task, and a Bayesian mixtu...