Use of the recognition heuristic depends on the domain's recognition validity, not on the recognition validity of selected sets of objects.

According to the recognition-heuristic theory, decision makers solve paired comparisons in which one object is recognized and the other not by recognition alone, inferring that recognized objects have higher criterion values than unrecognized ones. However, success-and thus usefulness-of this heuristic depends on the validity of recognition as a cue, and adaptive decision making, in turn, requires that decision makers are sensitive to it. To this end, decision makers could base their evaluation of the recognition validity either on the selected set of objects (the set's recognition validity), or on the underlying domain from which the objects were drawn (the domain's recognition validity). In two experiments, we manipulated the recognition validity both in the selected set of objects and between domains from which the sets were drawn. The results clearly show that use of the recognition heuristic depends on the domain's recognition validity, not on the set's recognition validity. In other words, participants treat all sets as roughly representative of the underlying domain and adjust their decision strategy adaptively (only) with respect to the more general environment rather than the specific items they are faced with.

The limited use of the fluency heuristic: Converging evidence across different procedures.

In paired comparisons based on which of two objects has the larger criterion value, decision makers could use the subjectively experienced difference in retrieval fluency of the objects as a cue. According to the fluency heuristic (FH) theory, decision makers use fluency-as indexed by recognition speed-as the only cue for pairs of recognized objects, and infer that the object retrieved more speedily has the larger criterion value (ignoring all other cues and information). Model-based analyses, however, have previously revealed that only a small portion of such inferences are indeed based on fluency alone. In the majority of cases, other information enters the decision process. However, due to the specific experimental procedures, the estimates of FH use are potentially biased: Some procedures may have led to an overestimated and others to an underestimated, or even to actually reduced, FH use. In the present article, we discuss and test the impacts of such procedural variations by reanalyzing 21 data sets. The results show noteworthy consistency across the procedural variations revealing low FH use. We discuss potential explanations and implications of this finding.

Whatever the cost? Information integration in memory-based inferences depends on cognitive effort.

One of the most prominent models of probabilistic inferences from memory is the simple recognition heuristic (RH). The RH theory assumes that judgments are based on recognition in isolation, such that other information is ignored. However, some prior research has shown that available knowledge is not generally ignored. In line with the notion of adaptive strategy selection--and, thus, a trade-off between accuracy and effort--we hypothesized that information integration crucially depends on how easily accessible information beyond recognition is, how much confidence decision makers have in this information, and how (cognitively) costly it is to acquire it. In three experiments, we thus manipulated (a) the availability of information beyond recognition, (b) the subjective usefulness of this information, and (c) the cognitive costs associated with acquiring this information. In line with the predictions, we found that RH use decreased substantially, the more easily and confidently information beyond recognition could be integrated, and increased substantially with increasing cognitive costs.

The role of subjective linear orders in probabilistic inferences.

In probabilistic inferences concerning which of two objects has the larger criterion value (e.g., which of two cities has more inhabitants), participants may recognize both objects, only one, or neither. According to the mental-toolbox approach, different decision strategies exist for each of these cases, utilizing different probabilistic cues. Possibly, however, participants use these cues to build a subjective rank order that involves all objects, irrespective of their recognition status. The decision process then simply utilizes the distance between two objects in one's subjective order. We tested the role of such linear orders in reanalyses of existing data and in a new experiment. Participants' choices and decision times were determined both by subjective rank-order distances and by the recognition status of the compared objects. To integrate these theoretically inconsistent findings, we discuss the role of the evidential difference (or the degree of conflict) between two objects.

A matter of time: antecedents of one-reason decision making based on recognition.

The notion of adaptive decision making implies that strategy selection in both inferences and preferences is driven by a trade-off between accuracy and effort. A strategy for probabilistic inferences which is particularly attractive from this point of view is the recognition heuristic (RH). It proposes that judgments rely on recognition in isolation-ignoring any further information that might be available-and thereby allows for substantial effort-reduction. Consequently, it is herein hypothesized that and tested whether increased necessity of effort-reduction-as implemented via time pressure-fosters reliance on the RH. Two experiments corroborated that this was the case, even with relatively mild time pressure. In addition, this result held even when non-compliance with the response deadline did not yield negative monetary consequences. The current investigations are among the first to tackle the largely open question of whether effort-related factors influence the reliance on heuristics in memory-based decisions.

Fluent, fast, and frugal? A formal model evaluation of the interplay between memory, fluency, and comparative judgments.

A new process model of the interplay between memory and judgment processes was recently suggested, assuming that retrieval fluency-that is, the speed with which objects are recognized-will determine inferences concerning such objects in a single-cue fashion. This aspect of the fluency heuristic, an extension of the recognition heuristic, has remained largely untested due to methodological difficulties. To overcome the latter, we propose a measurement model from the class of multinomial processing tree models that can estimate true single-cue reliance on recognition and retrieval fluency. We applied this model to aggregate and individual data from a probabilistic inference experiment and considered both goodness of fit and model complexity to evaluate different hypotheses. The results were relatively clear-cut, revealing that the fluency heuristic is an unlikely candidate for describing comparative judgments concerning recognized objects. These findings are discussed in light of a broader theoretical view on the interplay of memory and judgment processes.

A multiprocess account of hindsight bias in children.

In hindsight, that is, after receiving the correct answers to difficult questions, people's recall of their own prior answers tends to be biased toward the correct answers. We tested 139 participants from 3 age groups (9- and 12-year-olds and adults) in a hindsight-bias paradigm and found that all groups showed hindsight bias. Multinomial model-based analyses indicated that all age groups used the correct answers to reconstruct their original answers. In addition, the youngest group showed memory impairment caused by the presentation of the correct answers as well as an increased belief that they knew the correct answers all along. These results support a multiprocess explanation of hindsight bias in children.

One-reason decision making unveiled: a measurement model of the recognition heuristic.

The fast-and-frugal recognition heuristic (RH) theory provides a precise process description of comparative judgments. It claims that, in suitable domains, judgments between pairs of objects are based on recognition alone, whereas further knowledge is ignored. However, due to the confound between recognition and further knowledge, previous research lacked an unbiased measure of RH use. Also, model comparisons have not been based on goodness-of-fit and model complexity as criteria. To overcome both limitations we introduce and test a multinomial processing tree model showing that it fits empirical data and provides an unbiased measure of RH use. Analyses of 8 data sets reveal that the RH alone cannot account for the data, not even when it is implemented in a probabilistic way. That is, information integration beyond recognition plays a vital role and cannot merely account for empirical data better due to model flexibility. Also, we present several validations of the central model parameter and provide demonstrations of how the model can be applied to study the less-is-more effect as well as determinants of (and individual differences in) RH use. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Biased processing of threat-related information rather than knowledge deficits contributes to overestimation of threat in obsessive-compulsive disorder.

Overestimation of threat (OET) has been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). The present study deconstructed this complex concept and looked for specific deviances in OCD relative to controls. A total of 46 participants with OCD and 51 nonclinical controls were asked: (a) to estimate the incidence rate for 20 events relating to washing, checking, positive, or negative incidents. Furthermore, they were required (b) to assess their personal vulnerability to experience each event type, and (c) to judge the degree of accompanying worry. Later, participants were confronted with the correct statistics and asked (d) to rate their degree of worry versus relief. OCD participants did not provide higher estimates for OCD-related events than healthy participants, thus rendering a knowledge deficit unlikely. The usual unrealistic optimism bias was found in both groups but was markedly attenuated in OCD participants. OCD-related events worried OCD participants more than controls. Confrontation with the correct statistics appeased OCD participants less than healthy participants. Even in the case of large initial overestimations for OCD-related events, correct information appeased OCD participants significantly less than healthy participants. Our results suggest that OCD is not associated with a knowledge deficit regarding OCD-related events but that patients feel personally more vulnerable than nonclinical controls.

Ignorance- versus evidence-based decision making: a decision time analysis of the recognition heuristic.

According to part of the adaptive toolbox notion of decision making known as the recognition heuristic (RH), the decision process in comparative judgments-and its duration-is determined by whether recognition discriminates between objects. By contrast, some recently proposed alternative models predict that choices largely depend on the amount of evidence speaking for each of the objects and that decision times thus depend on the evidential difference between objects, or the degree of conflict between options. This article presents 3 experiments that tested predictions derived from the RH against those from alternative models. All experiments used naturally recognized objects without teaching participants any information and thus provided optimal conditions for application of the RH. However, results supported the alternative, evidence-based models and often conflicted with the RH. Recognition was not the key determinant of decision times, whereas differences between objects with respect to (both positive and negative) evidence predicted effects well. In sum, alternative models that allow for the integration of different pieces of information may well provide a better account of comparative judgments.

Recognizing users of the recognition heuristic.

The recognition heuristic is hypothesized to be a frugal inference strategy assuming that inferences are based on the recognition cue alone. This assumption, however, has been questioned by existing research. At the same time most studies rely on the proportion of choices consistent with the heuristic as a measure of its use which may not be fully appropriate. In this study, we propose an index to identify true users of the heuristic contrasting them to decision makers who incorporate further knowledge beyond recognition. The properties and the applicability of the proposed index are investigated in the reanalyses of four published experiments and corroborated by a new study drawn up to rectify the shortcomings of the reanalyzed experiments. Applying the proposed index to explore the influence of knowledge we found that participants who were more knowledgeable made use of the information available to them and achieved the highest proportion of correct inferences.

False beliefs maintenance for fear-related information in obsessive-compulsive disorder: an investigation with the hindsight paradigm.

The present study tested whether participants with obsessive-compulsive disorder (OCD) overestimate the incidence frequency of OCD-relevant phenomena and display a decreased hindsight bias for concern-related information, which may represent a maintenance factor for OCD. Thirty participants with OCD and 39 control participants were requested to estimate the incidence frequency of 8 events in each of 4 domains: washing-relevant, checking-relevant, negative, or neutral. Subsequently, participants received the correct statistics for all items and were requested to affectively appraise these. Two hours later participants had to reproduce their initial estimates. No differences emerged between participants with OCD and control participants regarding initial estimates. In case the frequency of an OCD-relevant item was initially largely overestimated, control participants expressed more relief when confronted with the correct solution than participants with OCD, especially for washing-relevant items. The recalled estimates showed a typical hindsight bias (i.e., the reproduced estimates were biased toward the correct response), but with no difference between groups. In sum, participants were normal in their subjective estimates of OCD-relevant events, and there was no evidence for a heightened maintenance of false beliefs.

Influence of factor V HR2 on thrombin generation and clinical manifestation in rare bleeding disorders.

In this study we investigated the influence of the presence of the factor V HR2 haplotype, defined by the factor V gene mutation H1299R (FV(HR2)), on thrombin generation. Measurements were performed in platelet-poor plasma of individuals with factor V(HR2) or factor V(Leiden) in comparison to a control group carrying none of these mutations. Coagulation was triggered by low concentrations of recombinant tissue factor in the presence of activated protein C. Thrombin generation was monitored by a fluorogenic substrate. The endogenous thrombin potential was calculated from the obtained curves. As a result we observed an increased thrombin generation both for individuals heterozygous and homozygous for FV(HR2). The level of endogenous thrombin potential is in the same range as in samples of patients heterozygous or homozygous for FV(Leiden). The results indicate that FV(HR2) plays a role as a risk factor for venous thrombosis in homozygous patients through an increased thrombin generation. The association between different clinical manifestations in individuals with FVII deficiency and endogenous thrombin potential and the presence of FV(HR2) was studied.

Research on hindsight bias: a rich past, a productive present, and a challenging future.

In this introduction to the present issue, we give a brief description of the phenomenon. Subsequently, we discuss the major theoretical accounts, focusing on how these are related to the papers included in the issue.

Hindsight bias as a function of anchor distance and anchor plausibility.

This study explored the influence of anchor distance on hindsight bias and how the subjective plausibility of different anchors moderates this relation. In addition to the standard memory design used in hindsight bias research, participants were asked to indicate the range of values for possible answers to difficult almanac questions. Varying anchor distance on the basis of each participant's individual range of possible answers showed (1) that anchor plausibility decreased with increasing anchor distance following a non-linear monotone function, (2) that size of hindsight bias initially increased with increasing anchor distance but, from a certain distance, started to decrease, and (3) that hindsight bias was found to be always higher for plausible than for implausible anchors.

SARA: a cognitive process model to simulate the anchoring effect and hindsight bias.

The cognitive process model "SARA" aims to explain the anchoring effect and hindsight bias by making detailed assumptions about the representation and alteration of item-specific knowledge. The model assumes that all processes, namely generating an estimate, encoding new information (i.e., the "anchor"), and reconstructing a previously generated estimate, are based on a probabilistic sampling process. Sampling probes long-term memory in order to retrieve information into working memory. Retrieval depends on the associative strength between this information and the currently active retrieval cues. Encoding the anchor may alter this associative pattern ("selective activation") or the anchor may serve as a retrieval cue, thus directing memory search ("biased reconstruction"). Both processes lead to systematically changed retrieval probabilities, thus causing the anchoring effect or hindsight bias. The model is completely formalised and implemented as a computer program. A series of simulations demonstrates the power of SARA to reproduce empirical findings and to predict new ones.

Hindsight bias in gustatory judgments.

Being in hindsight, people tend to overestimate what they had known in foresight. This phenomenon has been studied for a wide variety of knowledge domains (e.g., episodes with uncertain outcomes, or solutions to almanac questions). As a result of these studies, hindsight bias turned out to be a robust phenomenon. In this paper, we present two experiments that successfully extended the domain of hindsight bias to gustatory judgments. Participants tasted different food items and were asked to estimate the quantity of a certain ingredient, for example, the residual sugar in a white wine. Judgments in both experiments were systematically biased towards previously presented low or high values that were labeled as the true quantities. Thus, hindsight bias can be considered a phenomenon that extends well beyond the judgment domains studied so far.

Change of antibiotic susceptibility following periodontal therapy. A pilot study in aggressive periodontal disease.

BACKGROUND: The hypothesis was tested that bacterial susceptibilities in aggressive periodontitis change upon administration of systemic antibiotics as adjuncts to periodontal therapy. METHODS: In 23 subjects (average age 38.9+/-6.7 years) with aggressive periodontitis, microbial parameters were assessed prior to and 1 year after completion of comprehensive mechanical/surgical and systemic antimicrobial therapy. Following identification of five selected pathogens with the Rapid ID 32 A system, their susceptibilities towards amoxicillin/clavulanate potassium, metronidazole, and tetracycline were examined with the E-test. Antibiotics were administered according to the test results, and the minimal inhibitory concentrations (MIC90) were reevaluated after 1 year. Statistical analysis was performed on a patient basis, with the site data used for evaluation of the MIC levels. RESULTS: Bacterial MIC levels remained constant among the three antibiotic treatment groups compared with baseline. Mean MIC90 values ranged from <0.02 to 0.11 microg/ml (amoxicillin/clavulanate potassium), <0.02 to 0.27 microg/ml (metronidazole), and <0.02 to 0.11 microg/ml (tetracycline). Observed changes in susceptibility were attributed to the elimination of single bacterial taxa in the subgingival environment after antibiotic therapy. There were no statistically significant differences in clinical parameters among the treatment groups. Single tetracycline MICs were 1.5- to 6-fold enhanced compared to amoxicillin/clavulanate potassium and metronidazole. CONCLUSION: The periodontal pathogens investigated prior to and 1 year after periodontal therapy are tested sensitive to the antimicrobial agents. In aggressive periodontitis, changes in bacterial susceptibility upon the administration of systemic antibiotics are associated with the limited number of isolates tested following therapy.

Hindsight bias around the world.

Hindsight bias refers to the tendency to overestimate in hindsight what one has known in foresight. Recently, two experiments extended the research to include samples from different cultures (Choi & Nisbett, 2000; Heine & Lehman, 1996). Asking their participants what they would have guessed before they knew the outcome ("hypothetical design"), Choi and Nisbett (2000) found that Koreans, in comparison to North Americans, exhibited more hindsight bias. Heine and Lehman (1996), however, reported that Japanese people in comparison to Canadians showed marginally less hindsight bias. In a second study, in which participants were asked to recall what they had estimated before they knew the outcome ("memory design"), the latter authors found no difference in hindsight bias between Japanese people and Canadians. We extended these studies with 225 Internet participants, in a hypothetical design, from four different continents (Asia, Australia, Europe, and North America). Hindsight bias was large and similar for all samples except for German and Dutch participants who showed no hindsight bias at all. While the latter effect may be based on peculiarities of the material and of the participants, the former underscores the worldwide stability of the phenomenon. In addition a follow-up surprise rating (paper and pencil) in China (35 participants) and Germany (20 participants) revealed that only less surprising items led to hindsight bias while more surprising ones did not. We suggest that the basic cognitive processes leading to hindsight bias are by-products of the evolutionary-evolved capacity of adaptive learning. On top of these basic processes, individual meta-cognitions (e.g., elicited by surprise) or motives (e.g., a self-serving motive) may further moderate the amount of bias, thus explaining the diverging results of Choi and Nisbett (2000), Heine and Lehman (1996), and our own study.