Biomedical subjects

Ralph Hertwig

Publications and source records attributed to Ralph Hertwig.

12 recordsLinked to original sources

PubMed2025

An Updated Polygenic Index Repository: Expanded Phenotypes, New Cohorts, and Improved Causal Inference.

Polygenic indexes (PGIs) - DNA-based predictors of individual phenotypes - have become essential tools across biomedical and social sciences. We introduce Version 2 of the Polygenic Index Repository, which expands phenotype coverage from 47 to 61, increases the number of participating datasets from 11 to 20, and adopts a more consistent and improved methodology for PGI construction. For 16 phenotypes, we leverage summary statistics from an updated GWAS meta-analysis with greater statistical power compared to the original release, thereby improving the PGI's predictive power. To improve power for family-based analyses, we provide imputed parental PGIs in all datasets with first-degree relatives and offer a framework for interpreting results from analyses that control for parental PGIs. We illustrate the utility of parental PGIs using two applications: (1) comparing PGI associations with and without parental PGI controls for all phenotypes in two Repository datasets with family data, and (2) for BMI and diastolic blood pressure, exploring the contribution of causal versus non-causal components of PGI associations to the imperfect portability of PGIs across subgroups within a genetic ancestry. Collectively, the updates enhance predictive performance, broaden the Repository's scope, and introduce novel resources that reduce confounding bias and improve interpretability.

Journal Article↗

PubMed2006

The priority heuristic: making choices without trade-offs.

Bernoulli's framework of expected utility serves as a model for various psychological processes, including motivation, moral sense, attitudes, and decision making. To account for evidence at variance with expected utility, the authors generalize the framework of fast and frugal heuristics from inferences to preferences. The priority heuristic predicts (a) the Allais paradox, (b) risk aversion for gains if probabilities are high, (c) risk seeking for gains if probabilities are low (e.g., lottery tickets), (d) risk aversion for losses if probabilities are low (e.g., buying insurance), (e) risk seeking for losses if probabilities are high, (f) the certainty effect, (g) the possibility effect, and (h) intransitivities. The authors test how accurately the heuristic predicts people's choices, compared with previously proposed heuristics and 3 modifications of expected utility theory: security-potential/aspiration theory, transfer-of-attention-exchange model, and cumulative prospect theory.

Attention↗

PubMed2006

On the psychology of the recognition heuristic: retrieval primacy as a key determinant of its use.

The recognition heuristic is a prime example of a boundedly rational mind tool that rests on an evolved capacity, recognition, and exploits environmental structures. When originally proposed, it was conjectured that no other probabilistic cue reverses the recognition-based inference (D. G. Goldstein & G. Gigerenzer, 2002). More recent studies challenged this view and gave rise to the argument that recognition enters inferences just like any other probabilistic cue. By linking research on the heuristic with research on recognition memory, the authors argue that the retrieval of recognition information is not tantamount to the retrieval of other probabilistic cues. Specifically, the retrieval of subjective recognition precedes that of an objective probabilistic cue and occurs at little to no cognitive cost. This retrieval primacy gives rise to 2 predictions, both of which have been empirically supported: Inferences in line with the recognition heuristic (a) are made faster than inferences inconsistent with it and (b) are more prevalent under time pressure. Suspension of the heuristic, in contrast, requires additional time, and direct knowledge of the criterion variable, if available, can trigger such suspension.

Adult↗

PubMed2006

How to foster citizens' statistical reasoning: implications for genetic counseling.

OBJECTIVES: Our aim is to provide an overview of key research findings from cognitive psychology regarding effective ways of communicating statistical information, and to point out the implications of these findings for genetic testing. METHOD: We review the literature on the presentation of statistical information in diagnostic test results, discuss various representations that invite misunderstandings, and propose alternative representations that foster understanding. RESULTS: Single-event probabilities, conditional probabilities and relative risks are easily misunderstood. Specifying the class of events to which a probability refers and using natural frequency statements improve understanding. CONCLUSIONS: Cognitive psychology has identified simple and effective tools for improving statistical reasoning. They can help to improve the public's understanding of diagnostic test results.

Data Interpretation, Statistical↗

PubMed2005

How forgetting aids heuristic inference.

Some theorists, ranging from W. James (1890) to contemporary psychologists, have argued that forgetting is the key to proper functioning of memory. The authors elaborate on the notion of beneficial forgetting by proposing that loss of information aids inference heuristics that exploit mnemonic information. To this end, the authors bring together 2 research programs that take an ecological approach to studying cognition. Specifically, they implement fast and frugal heuristics within the ACT-R cognitive architecture. Simulations of the recognition heuristic, which relies on systematic failures of recognition to infer which of 2 objects scores higher on a criterion value, demonstrate that forgetting can boost accuracy by increasing the chances that only 1 object is recognized. Simulations of the fluency heuristic, which arrives at the same inference on the basis of the speed with which objects are recognized, indicate that forgetting aids the discrimination between the objects' recognition speeds.

Cognition↗

PubMed2005

Judgments of risk frequencies: tests of possible cognitive mechanisms.

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of estimates of absolute risk frequencies. Their nearly indistinguishable level of performance is remarkable given their different assumptions about the underlying cognitive processes and the fact that they give rise to different expectations regarding the accuracy of people's inferences. The authors discuss this seeming paradox, the lack of impact of financial incentives on judgmental accuracy, and the dominant interpretation of inaccurate inferences in terms of biased information processing.

Adult↗

PubMed2005

"A 30% chance of rain tomorrow": how does the public understand probabilistic weather forecasts?

The weather forecast says that there is a "30% chance of rain," and we think we understand what it means. This quantitative statement is assumed to be unambiguous and to convey more information than does a qualitative statement like "It might rain tomorrow." Because the forecast is expressed as a single-event probability, however, it does not specify the class of events it refers to. Therefore, even numerical probabilities can be interpreted by members of the public in multiple, mutually contradictory ways. To find out whether the same statement about rain probability evokes various interpretations, we randomly surveyed pedestrians in five metropolises located in countries that have had different degrees of exposure to probabilistic forecasts--Amsterdam, Athens, Berlin, Milan, and New York. They were asked what a "30% chance of rain tomorrow" means both in a multiple-choice and a free-response format. Only in New York did a majority of them supply the standard meteorological interpretation, namely, that when the weather conditions are like today, in 3 out of 10 cases there will be (at least a trace of) rain the next day. In each of the European cities, this alternative was judged as the least appropriate. The preferred interpretation in Europe was that it will rain tomorrow "30% of the time," followed by "in 30% of the area." To improve risk communication with the public, experts need to specify the reference class, that is, the class of events to which a single-event probability refers.

Journal Article↗

PubMed2004

The role of representative design in an ecological approach to cognition.

Egon Brunswik argued that psychological processes are adapted to environmental properties. He proposed the method of representative design to capture these processes and advocated that psychology be a science of organism-environment relations. Representative design involves randomly sampling stimuli from the environment or creating stimuli in which environmental properties are preserved. This departs from systematic design. The authors review the development of representative design, examine its use in judgment and decision-making research, and demonstrate the effect of design on research findings. They suggest that some of the practical difficulties associated with representative design may be overcome with modern technologies. The importance of representative design in psychology and the implications of this method for ecological approaches to cognition are discussed.

Adaptation, Psychological↗

PubMed2004

Decisions from experience and the effect of rare events in risky choice.

When people have access to information sources such as newspaper weather forecasts, drug-package inserts, and mutual-fund brochures, all of which provide convenient descriptions of risky prospects, they can make decisions from description. When people must decide whether to back up their computer's hard drive, cross a busy street, or go out on a date, however, they typically do not have any summary description of the possible outcomes or their likelihoods. For such decisions, people can call only on their own encounters with such prospects, making decisions from experience. Decisions from experience and decisions from description can lead to dramatically different choice behavior. In the case of decisions from description, people make choices as if they overweight the probability of rare events, as described by prospect theory. We found that in the case of decisions from experience, in contrast, people make choices as if they underweight the probability of rare events, and we explored the impact of two possible causes of this underweighting--reliance on relatively small samples of information and overweighting of recently sampled information. We conclude with a call for two different theories of risky choice.

Choice Behavior↗

PubMed2003

How to keep children safe in traffic: find the daredevils early.

Crossing the street in front of oncoming vehicles poses serious danger to young children. But is each young pedestrian similarly at risk? The authors aimed to identify children who are particularly prone to making risky and potentially harmful crossing decisions. They used a simple game involving risk to classify 5- to 6-year-olds as risk takers or risk avoiders. Children classified as risk takers made more crossing decisions at a busy 1-way street than risk avoiders, tolerated shorter time intervals between initiation of the crossing decision and arrival of the next vehicle, and were more likely to cause a (hypothetical) accident. Finally, they made decisions more quickly than risk avoiders. The authors discuss the implication of these results for traffic safety programs.

Accidents, Traffic↗

PubMed2002

Parental investment: how an equity motive can produce inequality.

The equity heuristic is a decision rule specifying that parents should attempt to subdivide resources more or less equally among their children. This investment rule coincides with the prescription from optimality models in economics and biology in cases in which expected future return for each offspring is equal. In this article, the authors present a counterintuitive implication of the equity heuristic: Whereas an equity motive produces a fair distribution at any given point in time, it yields a cumulative distribution of investments that is unequal. The authors test this analytical observation against evidence reported in studies exploring parental investment and show how the equity heuristic can provide an explanation of why the literature reports a diversity of birth order effects with respect to parental resource allocation.

Birth Order↗

PubMedDate not supplied

Hindsight bias: how knowledge and heuristics affect our reconstruction of the past.

Once people know the outcome of an event, they tend to overestimate what could have been anticipated in foresight. Although typically considered to be a robust phenomenon, this hindsight bias is subject to moderating circumstances. In their meta-analysis, Christensen-Szalanski and Willham (1991) observed that the more experience people have with the task under consideration, the smaller is the resulting hindsight bias. This observation is one benchmark against which the explanatory power of process models of hindsight bias can be measured. Therefore, we used it to put the recently proposed RAFT model (Hoffrage, Hertwig, & Gigerenzer, 2000) to another test. Our findings were consistent with the "expertise effect." Specifically, we observed-using computer simulations of the RAFT model-that the more comprehensive people's knowledge is in foresight, the smaller is their hindsight bias. In addition, we made two counterintuitive observations: First, the relation between foresight knowledge and hindsight bias appears to be independent of how knowledge is processed. Second, even if foresight knowledge is false, it can reduce hindsight bias. We conclude with a discussion of the functional value of hindsight bias.

Computer Simulation↗