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As food technology continues to advance, the potential for new food products to enter the food market grows, attracting considerable media interest. Whilst previous research has explored public per...

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 evidence of optimistic belief updating may be the result of flaws in experimental design, rather than motivated reasoning. In light of this controversy, we conduct three pre-registered variations of the standard belief updating paradigm (combined N = 300) in which we test for asymmetric belief updating with neutral, non-valenced stimuli using analytic approaches found in previous research. We find evidence of seemingly biased belief updating with neutral stimuli — results that cannot be attributed to a motivational, valence-based, optimism account — and further show that there is uninterpretable variability across samples and analytic techniques. Jointly, these results serve to highlight the methodological flaws in current optimistic belief updating research.

The informational leakage account of attribute framing effects proposes that a communicator's choice of frame provides informational value, such that different frames are not informationally equivalent. Across five studies communicating food risks, we investigated the adaptability of communication recipients' (our participants) use of frame information by manipulating the degree to which the communicator ostensibly had a choice over how the information was framed. Within-participants framing effects were observed across all conditions of all studies. Only in Study 4 (the only study in which communicator choice was manipulated within-participants) was there any evidence for an attenuation of framing effects where the communicator was not responsible for how the information was framed. Overall, regardless of whether or not framing effects are driven by the informational value contained in a communicator's choice of frame, people show little sensitivity to situations where that choice is removed.

Within UK policing it is routinely the responsibility of fingerprint laboratory practitioners to chemically develop areas of latent fingerprint ridge detail on evidential items and to determine which areas of ridge detail are of sufficient quality to be submitted to fingerprint experts for search or comparison against persons of interest. This study assessed the effectiveness of the fingermark submission process within the Evidence Recovery Unit Fingerprint Laboratory of the Metropolitan Police Service. Laboratory practitioners were presented with known source fingermark images previously deemed identifiable or insufficient by fingerprint experts, and were asked to state which of the marks they would forward to the Fingerprint Bureau. The results indicated that practitioners forwarded a higher percentage of insufficient fingermarks than is acceptable according to current laboratory guidelines, and discarded a number of marks that were of sufficient quality for analysis. Practitioners forwarded more insufficient fingermarks when considering fingermarks thought to be related to a murder and discarded more sufficient fingermarks when considering those thought to be related to a crime of ‘theft from vehicle’. The results highlight the need for fingerprint laboratories to work alongside fingerprint experts to ensure that a consistent approach to decision-making is, as far as possible, achieved, and that appropriate thresholds are adopted so as to prevent the loss of valuable evidence and improve the efficiency of the fingerprint filtering process.

The public expects science to reduce or eliminate uncertainty (Kinzig & Starrett, 2003), yet scientific forecasts are probabilistic (at best) and it is simply not possible to make predictions with certainty. Whilst an ‘unlikely’ outcome is not expected to occur, an ‘unlikely’ outcome will still occur one in five times (based on a translation of 20%, e.g. Theil, 2002), according to a frequentist perspective. When an ‘unlikely’ outcome does occur, the prediction may be deemed ‘erroneous’, reflecting a misunderstanding of the nature of uncertainty. Such misunderstandings could have ramifications for the subsequent (perceived) credibility of the communicator who made such a prediction. We examine whether the effect of ‘erroneous’ predictions on perceived credibility differs according to the communication format used. Specifically, we consider verbal, numerical (point and range [wide / narrow]) and mixed format probability expressions. We consistently find that subsequent perceptions are least affected by the ‘erroneous’ prediction when it is expressed numerically, regardless of whether it is a point or range estimate. Our findings suggest numbers should be used in consequential risk communications regarding ‘unlikely’ events, wherever possible.

In the absence of an objective contingency, psychological studies have shown that people nevertheless attribute outcomes to their own actions. Thus, by wrongly inferring control in chance situations people appear to hold false beliefs concerning their agency, and are said to succumb to an illusion of control (IoC). In the current article, we challenge traditional conceptualizations of the illusion by examining the thesis that the IoC reflects rational and adaptive decision making. Firstly, we propose that the IoC is a by-product of a rational uncertain judgment (“the likelihood that I have control over a particular outcome”). We adopt a Bayesian perspective to demonstrate that, given their past experience, people should be prone to ascribing skill to chance outcomes in certain situations where objectively control does not exist. Moreover, existing empirical evidence from the IoC literature is shown to support such an account. Secondly, from a decision-theoretic perspective, in many consequential situations, underestimating the chance of controlling a situation carries more costs than overestimating that chance. Thus, situations will arise in which people will incorrectly assign control to events in which outcomes result from chance, but the attribution is based on rational processes.

Adults and children have recently been shown to prefer guessing the outcome of a die roll after the die has been rolled (but remained out of sight) rather than before it has been rolled. This result is contrary to the predictions of the competence hypothesis (Heath & Tversky, 1991), which proposes that people are sensitive to the degree of their relative ignorance and therefore prefer to guess about an outcome it is impossible to know, rather than one that they could know, but do not. We investigated the potential role of agency in guessing preferences about a novel game of chance. When the experimenter controlled the outcome, we replicated the finding that adults and 5- to 6-year-old children preferred to make their guess after the outcome had been determined. For adults only, this preference reversed when they exerted control over the outcome about which they were guessing. The adult data appear best explained by a modified version of the competence hypothesis that highlights the notion of control or responsibility. It is proposed that potential attributions of blame are related to the guesser's role in determining the outcome. The child data were consistent with an imagination-based account of guessing preferences.

Repayment decisions—how much of the loan to repay and when to make the payments—directly influence consumer debt levels. The authors examine how minimum required payment policy and loan information disclosed to consumers influence repayment decisions. They find that while presenting minimum required payment information has a negative impact on repayment decisions, increasing the minimum required level has a positive effect on repayment for most consumers. Experimental evidence from U.S. consumers shows that consumers’ propensity to pay the minimum required each month moderates these effects; U.K. credit card field data indicate that borrowers’ credit limit and balance due also moderate these effects. However, increasing the minimum level is unlikely to completely eliminate the negative effect of presenting minimum payment information. In addition, disclosing supplemental information, such as future interest cost and time needed to repay the loan, does not reduce the negative effects of including minimum payment information and has no substantial positive effect on repayments. This research offers new insights into the debt repayment process and has implications for consumers, lenders, and public policy.

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 patterns commonly interpreted as indicative of optimism for purely statistical reasons. Specifically, we show how extant data from unrealistic optimism studies investigating people's comparative risk judgments are plagued by the statistical consequences of sampling constraints and the response scales used, in combination with the comparative rarity of truly negative events. We conclude that the presence of such statistical artifacts raises questions over the very existence of an optimistic bias about risk and implies that to the extent that such a bias exists, we know considerably less about its magnitude, mechanisms, and moderators than previously assumed.

Possible measures to mitigate climate change require global collective actions whose impacts will be felt by many, if not all. Implementing such actions requires successful communication of the reasons for them, and hence the underlying climate science, to a degree that far exceeds typical scientific issues which do not require large-scale societal response. Empirical studies have identified factors, such as the perceived level of consensus in scientific opinion and the perceived reliability of scientists, that can limit people's trust in science communicators and their subsequent acceptance of climate change claims. Little consideration has been given, however, to recent formal results within philosophy concerning the relationship between truth, the reliability of evidence sources, the coherence of multiple pieces of evidence/testimonies, and the impact of (non-)independence between sources of evidence. This study draws on these results to evaluate exactly what has (and, more important, has not yet) been established in the empirical literature about the factors that bias the public's reception of scientific communications about climate change.

Philosophers have become increasingly interested in testimony (e.g. Coady, Testimony: A philosophical study. Oxford University Press, Oxford, 1992; Kusch & Lipton, Stud Hist Philos Sci 33:209–217). In the context of argumentation and persuasion, the distinction between the content of a message and its source is a natural and important one. The distinction has consequently attracted considerable attention within psychological research. There has also been a range of normative attempts to deal with the question of how source and message characteristics should combine to give rise to an overall evaluation of evidential strength (e.g. Walton, Witness testimony evidence: Argumentation, artificial intelligence, and law. Cambridge University Press, Cambridge, 2008). This chapter treats this issue from the perspective of the Bayesian approach to argument (Hahn & Oaksford, Psychol Rev 114:704–732, 2007a; Hahn et al., Informal Log 29:337–367, 2009) and summarises empirical evidence on key intuitions.

How well we are attuned to the statistics of our environment is a fundamental question in understanding human behaviour. It seems particularly important to be able to provide accurate assessments of the probability with which negative events occur so as to guide rational choice of preventative actions. One question that arises here is whether or not our probability estimates for negative events are systematically biased by their severity. In a minimal experimental context involving an unambiguous, objective representation of probability, we found that participants judged a controllable event as more likely to occur when its utility was extremely negative than when it was more neutral. A decision-theoretic explanation based on loss function asymmetries is advanced which supports the claim that probability estimates are not intrinsically biased by utilities.