Semantic cross-scale numerical anchoring

Anchoring effects are robust, varied and can be consequential. Researchers have provided a variety of alternative explanations for these effects. More recently, it has become apparent that anchoring effects might be produced by a variety of different processes, either acting simultaneously, or else individually in distinct situations. An unresolved issue is whether anchoring, aside from simple numeric priming, can transcend scales. That is, is it necessary that the anchor value and the target judgment are expressed in the same units? Despite some theoretical predictions to the contrary, this paper demonstrates semantic cross-scale anchoring in four experiments. Such effects are important for the direction of future theorising on the causes of anchoring effects and understanding the scope of their consequences in applied domains

Conceptual and direct replications fail to support the stake-likelihood hypothesis as an explanation for the interdependence of utility and likelihood judgments

Previous research suggests that we systematically overestimate the occurrence of both positive and negative events, compared to neutral future events, and that these biases are due to a misattribution of arousal elicited by utility (Stake-Likelihood Hypothesis, SLH, Vosgerau, 2010). However, extant research has provided only indirect support for these arousal misattribution processes. In the present research, we initially aimed to provide a direct test of the SLH by measuring arousal with galvanic skin responses to examine the mediating role of arousal. We observed no evidence that measured arousal mediated the impact of utility on probability estimates. Given the lack of direct support for the SLH in Experiment 1, Experiments 2-5 aimed to assess the SLH by replicating some of the original findings that provided support for arousal misattribution as a mechanism. Despite our best efforts to create experimental conditions under which we would be able to demonstrate the stake-likelihood effect, we were unable to replicate previous results, with a Bayesian meta-analysis demonstrating support for the null hypothesis. We propose that accounts based on imaginability and loss function asymmetry are currently better candidate explanations for the influence of outcome utility on probability estimates

Understanding the coherence of the severity effect and optimism phenomena: Lessons from attention

Claims that optimism is a near-universal characteristic of human judgment seem to be at odds with recent results from the judgment and decision making literature suggesting that the likelihood of negative outcomes are overestimated relative to neutral outcomes. In an attempt to reconcile these seemingly contrasting phenomena, inspiration is drawn from the attention literature in which there is evidence that both positive and negative stimuli can have attentional privilege relative to neutral stimuli. This result provides a framework within which I consider three example phenomena that purport to demonstrate that people’s likelihood estimates are optimistic: Wishful thinking; Unrealistic comparative optimism and Asymmetric belief updating. The framework clarifies the relationships between these phenomena and stimulates future research questions. Generally, whilst results from the first two phenomena appear reconcilable in this conceptualisation, further research is required in reconciling the third

'Unlikely' outcomes might never occur, but what about 'unlikely (20% chance)' outcomes?

A commonly suggested solution to reduce misinterpretations of verbal probability expressions in risk communications is to use a verbal-numerical (mixed format) approach, but it is not known whether this increases understanding over and above a purely numerical format. Using the ‘which outcome’ methodology (Teigen & Filkuková, 2013), we examined the effect of using verbal, numerical and mixed communication formats, as well as investigating whether marking outcomes as salient would alter the outcomes people perceived as ‘unlikely’ or having a 20% chance of occurring. We observed no effect of saliency, but replicated previous findings, with general preference for values at the high end of a distribution (including maximum/above maximum values) present in both verbal and mixed communication formats. This demonstrates the relevance of these findings for real-world consequential risk communication. Whilst the estimates differed between the mixed and numerical formats, we fo

How many laypeople holding a popular opinion are needed to counter an expert opinion?

In everyday situations, people regularly receive information from large groups of (lay) people and from single experts. Although lay opinions and expert opinions have been studied extensively in isolation, the present study examined the relationship between the two by asking how many laypeople are needed to counter an expert opinion. A Bayesian formalisation allowed the prescription of this quantity. Participants were subsequently asked to assess how many laypeople are needed in different situations. The results demonstrate that people are sensitive to the relevant factors identified for determining how many lay opinions are required to counteract a single expert opinion. People's assessments were fairly good in line with Bayesian predictions

Maintaining credibility when communicating uncertainty: The role of communication format

Research into risk communication has commonly highlighted the disparity between the meaning intended by the communicator and what is understood by the recipient. Such miscommunications will have implications for perceived trust and expertise of the communicator, but it is not known whether this differs according to the communication format. We examined the effect of using verbal, numerical and mixed communication formats on perceptions of credibility and correctness, as well as whether they influenced a decision to evacuate, both before and after an ‘erroneous’ prediction (i.e. an ‘unlikely’ event occurs, or a ‘likely’ event does not occur). We observed no effect of communication format on any of the measures pre-outcome, but found the numerical format was perceived as less incorrect, as well as more credible than the other formats after an ‘erroneous’ prediction, but only when low probability expressions were used. Our findings suggest numbers should be used in consequential risk communications

Understanding ‘Unlikely (20% Likelihood)’ or ‘20% Likelihood (Unlikely)’ Outcomes: The Robustness of the Extremity Effect

Calls to communicate uncertainty using mixed, verbal‐numerical formats (‘unlikely [0–33%]’) have stemmed from research comparing mixed with solely verbal communications. Research using the new ‘which outcome’ approach to investigate understanding of verbal probability expressions suggests, however, that mixed formats might convey disadvantages compared with purely numerical communications. When asked to indicate an outcome that is ‘unlikely’, participants have been shown to often indicate outcomes with a value exceeding the maximum value shown, equivalent to a 0% probability —an ‘extremity effect’. Recognising the potential consequences of communication recipients expecting an ‘unlikely’ event to never occur, we extend the ‘which outcome’ work across four experiments, using verbal, numerical, and verbal‐numerical communication formats, as well as a previously unconsidered numerical‐verbal format. We examine how robust the effect is in the context of consequential outcomes and over non‐normal distributions. We also investigate whether participants are aware of the inconsistency in their responses from a traditional ‘how likely’ and ‘which outcome’ task. We replicate and extend previous findings, with preference for extreme outcomes (including above maximum values) observed in both verbal and verbal‐numerical formats. Our results suggest caution in blanket usage of recently recommended verbal‐numerical formats for the communication of uncertainty

Anchoring climate change communications

Verbal probability expressions (VPEs) are frequently used to communicate risk and uncertainty. The Intergovernmental Panel on Climate Change attempts to standardise the use and interpretation of these expressions through a translation scale of numerical ranges to VPEs. A common issue in interpreting VPEs is the tendency for individuals to interpret VPEs around the mid-point of the scale (i.e., around 50%). Previous research has shown that compliance with the IPCC’s standards can be improved if the numerical translation is presented simultaneously with the VPE, reducing the regressiveness of interpretations. We show that an explicit statement of the lower or upper bound implied by the expression (e.g., 0-33%; 66-100%) leads to better differentiated estimates of the probability implied by ‘likely’ and ‘unlikely’ than when the bound is not explicitly identified (e.g., less than 33%; greater than 66%)

Near-real-time service provision during effusive crises at Etna and Stromboli: basis and implementation of satellite-based IR operations

Using the NEODAAS-Dundee AVHRR receiving station (Scotland), NEODAAS-Plymouth can provide calibrated brightness temperature data to end users or interim users in near-real time. Between 2000 and 2009 these data were used to undertake volcano hot spot detection, reporting and time-average discharge rate dissemination during effusive crises at Mount Etna and Stromboli (Italy). Data were passed via FTP, within an hour of image generation, to the hot spot detection system maintained at Hawaii Institute of Geophysics and Planetology (HIGP, University of Hawaii at Manoa, Honolulu, USA). Final product generation and quality control were completed manually at HIGP once a day, so as to provide information to onsite monitoring agencies for their incorporation into daily reporting duties to Italian Civil Protection. We here describe the processing and dissemination chain, which was designed so as to provide timely, useable, quality-controlled and relevant information for ‘one voice’ reporting by the responsible monitoring agencies

An appropriate verbal probability lexicon for communicating surgical risks is unlikely to exist

Effective risk communication about medical procedures is critical to ethical shared decision-making. Here, we explore the potential for development of an evidence-based lexicon for verbal communication of surgical risk. We found that Ear, Nose and Throat (ENT) surgeons expressed a preference for communicating such risks using verbal probability expressions (VPEs; e.g., “high risk”). However, there was considerable heterogeneity in the expressions they reported using (Study 1). Study 2 compared ENT surgeons’ and laypeople’s (i.e., potential patients) interpretations of the ten most frequent VPEs listed in Study 1. While both groups displayed considerable variability in interpretations, lay participants demonstrated more, as well as providing systematically higher interpretations than those of surgeons. Study 3 found that lay participants were typically unable to provide unique VPEs to differentiate between the ranges of (low) probabilities required. Taken together, these results add to arguments that reliance on VPEs for surgical risk communication is ill-advised. Not only are there systematic interpretational differences between surgeons and potential patients, but the coarse granularity of VPEs raises severe challenges for developing an appropriate evidence-based lexicon for surgical risk communication. We caution against the use of VPEs in any risk context characterized by low, but very different, probabilities. (PsycInfo Database Record (c) 2022 APA, all rights reserved