The nature of anchor-biased estimates and its application to the wisdom of crowds.

We propose a method to achieve better wisdom of crowds by utilizing anchoring effects. In this method, people are first asked to make a comparative judgment such as "Is the number of new COVID-19 infections one month later more or less than 10 (or 200,000)?" As in this example, two sufficiently different anchors (e.g., "10" or "200,000") are set in the comparative judgment. After this comparative judgment, people are asked to make their own estimates. These estimates are then aggregated. We hypothesized that the aggregated estimates using this method would be more accurate than those without anchor presentation. To examine the effectiveness of the proposed method, we conducted three studies: a computer simulation and two behavioral experiments (numerical estimation of perceptual stimuli and estimation of new COVID-19 infections by physicians). Through computer simulations, we could identify situations in which the proposed method is effective. Although the proposed method is not always effective (e.g., when a group can make fairly accurate estimations), on average, the proposed method is more likely to achieve better wisdom of crowds. In particular, when a group cannot make accurate estimations (i.e., shows biases such as overestimation or underestimation), the proposed method can achieve better wisdom of crowds. The results of the behavioral experiments were consistent with the computer simulation findings. The proposed method achieved better wisdom of crowds. We discuss new insights into anchoring effects and methods for inducing diverse opinions from group members.

Exploration of appropriate media to influence sustainable on-site sanitation choices in Sri Lanka- visualization with still images or a video.

Pit latrines are the most common form of improved sanitation in many rapidly developing countries. However, they cause the highest amount of groundwater pollution among on-site sanitation (OSS) facilities. Many households in developing countries use groundwater as their main or sub-source, and pit latrines are not a sustainable solution. Thus, the conversion from pit latrines to septic tanks is required. We created two types of media, still images and a video, to illustrate the differences in functions and hygiene risks between pit latrines and septic tanks. Moreover, a survey was conducted in Sri Lanka to determine the media choice that would increase the people's preference for septic tanks as their next OSS, even weeks after the information is presented. The choice of the next OSS participants selected before they were presented with the images was the same as that currently in use, reflecting the belief that the problem of pit latrines was not currently apparent and need not be changed. However, a video presentation of the information made it possible for a larger group of people to choose the usage of septic tanks in the future, especially in suburban areas where the problems were likely to occur.

Can individual subjective confidence in training questions predict group performance in test questions?

When people have to solve many tasks, they can aggregate diverse individuals' judgments using the majority rule, which often improves the accuracy of judgments (wisdom of crowds). When aggregating judgments, individuals' subjective confidence is a useful cue for deciding which judgments to accept. However, can confidence in one task set predict performance not only in the same task set, but also in another? We examined this issue through computer simulations using behavioral data obtained from binary-choice experimental tasks. In our simulations, we developed a "training-test" approach: We split the questions used in the behavioral experiments into "training questions" (as questions to identify individuals' confidence levels) and "test questions" (as questions to be solved), similar to the cross-validation method in machine learning. We found that (i) through analyses of behavioral data, confidence in a certain question could predict accuracy in the same question, but not always well in another question. (ii) Through a computer simulation for the accordance of two individuals' judgments, individuals with high confidence in one training question tended to make less diverse judgments in other test questions. (iii) Through a computer simulation of group judgments, the groups constructed from individuals with high confidence in the training question(s) generally performed well; however, their performance sometimes largely decreased in the test questions especially when only one training question was available. These results suggest that when situations are highly uncertain, an effective strategy is to aggregate various individuals regardless of confidence levels in the training questions to avoid decreasing the group accuracy in test questions. We believe that our simulations, which follow a "training-test" approach, provide practical implications in terms of retaining groups' ability to solve many tasks.

Effect of asking questions and providing knowledge on attitudes toward organic foods among Japanese consumers.

Some people overestimate the benefits of certain kinds of foods, such as organic foods, while others underestimate it. Previous studies have found that reducing people's self-assessed knowledge successfully moderated these extreme attitudes. In this study, we investigated interventions to reduce people's self-assessed knowledge and to moderate attitude extremity. We examined extreme attitudes toward organic foods and investigated the effects of implementing two intervention methods to moderate their attitude: (1) providing knowledge on organic food after asking them some questions and (2) simply providing them with knowledge. We conducted a two-factor mixed-design experiment with 653 college-educated Japanese women. In the first condition, before knowledge provision, participants were asked to answer questions about organic foods and were then informed of the correct answer and whether their answer was correct (Q&A Intervention). This step was based on an intervention conducted in a previous study to reduce their self-assessed factual knowledge. In the second condition, participants were simply provided with knowledge without being asked to answer any questions (Simple Intervention). The results showed that both intervention methods, on average, decreased the participants' self-assessed knowledge and attitude extremity. Therefore, simply providing knowledge may be effective in reducing their self-assessed factual knowledge and moderating their extreme attitudes toward organic foods.

A simple cognitive method to improve the prediction of matters of taste by exploiting the within-person wisdom-of-crowd effect.

In our daily lives, we must often predict the level of others' satisfaction with something they have not experienced thus far. How can such a prediction be accurate? Existing studies indicate that, by referring to the extent to which people themselves have enjoyed something, they are able to predict others' future satisfaction, to some extent. In this study, we propose a method that can further improve such predictions. This method is expected to allow individuals to exploit the 'wisdom of the crowd' within a person, in terms of taste. Specifically, for a single target, participants in our study group produced two opinions from different perspectives: the degree to which they preferred something, and they estimated 'public opinion'. Utilising two behavioural studies and computer simulations, we confirmed the effectiveness of our method; specifically, blending the two opinions could enhance an individual's prediction ability. Subsequently, we mathematically analysed how effective our method is and identified several factors that influenced its efficiency. Our findings offer several contributions to 'wisdom-of-crowd' research.

On the round number bias and wisdom of crowds in different response formats for numerical estimation.

When asked for numerical estimations, people can respond by stating their estimates (e.g., writing down a number) or indicating a number on a scale. Although these methods are logically the same, such differences may affect the responses to the numerical estimations. In this study, we examined how differences in response format affected responses to numerical estimations using two behavioral experiments. We found that participants showed a round number bias (i.e., people answered estimates with round numbers) when simply stating a number and the distribution of responses tended to be less diverse. In contrast, this tendency was not observed when the participants responded using a scale. Participants provided more diverse estimates when they answered using a scale. Furthermore, we analyzed how this difference in response distribution was related to the wisdom of crowds (the aggregated judgment is as accurate as, or sometimes better than, the best individual judgment in the group) using computer simulations. The results indicated that round number bias affected the achievement of the wisdom of crowds. Particularly, when the group size was small, biased responses resulted in less effective achievement. Our findings suggest that using an appropriate scale is a low-cost method for eliminating round number bias and efficiently achieving the wisdom of crowds.

Two Cases of Hemorrhagic Ampullary Lesions Successfully Treated by Endoscopic Papillectomy.

We herein report two cases of hemorrhagic ampullary lesions in which endoscopic papillotomy was performed to control bleeding and resulted in successful treatment. Both patients were pathologically diagnosed with an underlying pathology characterized by inflammatory cell infiltration and capillary proliferation. They also had disposing factors for bleeding, such as antithrombotic therapy and idiopathic thrombocytopenic purpura. Endoscopic treatment was selected because the risk of surgical resection was high due to the patients' hemorrhagic condition. Both patients were successfully treated without any serious adverse events and had an uneventful postoperative course with no relapse of bleeding.

What Stimuli Are Necessary for Anchoring Effects to Occur?

The anchoring effect is a form of cognitive bias in which exposure to some piece of information affects its subsequent numerical estimation. Previous studies have discussed which stimuli, such as numbers or semantic priming stimuli, are most likely to induce anchoring effects. However, it has not been determined whether anchoring effects will occur when a number is presented alone or when the semantic priming stimuli have an equivalent dimension between a target and the stimuli without a number. We conducted five experimental studies (N = 493) using stimuli to induce anchoring effects. We found that anchoring effects did not occur when a number was presented alone or when phrases to induce semantic priming were used without presenting a number. These results indicate that both numerical and semantic priming stimuli must be presented for anchoring effects to occur. Our findings represent a substantial contribution to the literature on anchoring effects by offering insights into how these effects are generated.

Self-Initiated Actions Under Different Choice Architectures Affect Framing and Target Evaluation Even Without Verbal Manipulation.

Logically equivalent but different descriptions (i.e., manipulation of verbal expressions) affect decision-making in a phenomenon known as the framing effect. A choice architecture changes decision-makers' actions, which in turn create different frames, but little is known about whether the frame created by their action can change their judgments. We examined whether self-initiated action induced by a choice architecture changed evaluations. In two experimental studies (N = 271), we found that self-initiated actions whose final goal was completely the same and for which no verbal expressions were manipulated led to different evaluations. In particular, we found that a difference in the placement of rewards, which required participants to behave differently, changed their ratings of satisfaction with the rewards. This study provides evidence that the framing effect can occur without verbal manipulation. This finding advances our understanding of how participants' actions lead to different evaluations.

Special Number or a Mere Numerical Array? Effect of Repdigits on Judgments and Choices.

Previous studies have shown that people find special meaning in numerical arrays. In this article, we have focused on the features of numerical arrays, repdigits (e.g., "777"), and examined the effect of repdigits on judgments and choices. We formulated the following hypotheses: (1) when people want to assign special meanings to numbers [in the case of purchase or choice of alternatives that contain numbers (e.g., serial numbers)], repdigits will be chosen since people tend to prefer numbers that contain repdigits, and (2) when people think about probabilistic or statistical events involving numerical arrays, they will regard repdigits as a mere set of numerical arrays, and preference for them will disappear. Through five behavioral experiments, we examined these two hypotheses and the results generally supported them. We also discussed the features and psychological processes of repdigits in judgments and choices.

Water demand management: Visualising a public good.

Recent studies on water demand management show that providing visual information on water usage along with social comparisons with neighbouring households resulted in more efficient water usage. However, social comparisons can be discomforting for participants, especially in the case of downward or negative evaluations. To avoid this, some studies promote the use of social identity, a social norm approach that avoids comparisons. Past studies using social comparison used infographics, whereas other study types have used only textual (non-graphic) information. Therefore, in this study, we created a visualisation of water usage to highlight the importance of water as a shared resource, that is, as a public good, and feedback over six months according to the participants' water usage. A difference-in-difference analysis indicated that the feedback was marginally significant in decreasing water consumption immediately and continuously, especially for the middle and low use households, during the summer months, which is a period of perceived water shortage. From the questionnaire survey, we found that households felt that they determined their water usage based on their preference and were satisfied with the outcome.

Familiarity-Matching: An Ecologically Rational Heuristic for the Relationships-Comparison Task.

Previous studies have shown that people often use heuristics in making inferences and that subjective memory experiences, such as recognition or familiarity of objects, can be valid cues for inferences. So far, many researchers have used the binary choice task in which two objects are presented as alternatives (e.g., "Which city has the larger population, city A or city B?"). However, objects can be presented not only as alternatives but also in a question (e.g., "Which country is city X in, country A or country B?"). In such a situation, people can make inferences based on the relationship between the object in the question and each object given as an alternative. In the present study, we call this type of task a "relationships-comparison task." We modeled the three inference strategies that people could apply to solve it (familiarity-matching [FM; a new heuristic we propose in this study], familiarity heuristic [FH], and knowledge-based inference [KI]) to examine people's inference processes. Through Studies 1, 2, and 3, we found that (a) people tended to rely on heuristics, and that FM (inferences based on similarity in familiarity between objects) well explained participants' inference patterns; (b) FM could work as an ecologically rational strategy for the relationships-comparison task since it could effectively reflect environmental structures, and that the use of FM could be highly replicable and robust; and (c) people could sometimes use a decision strategy like FM, even in their daily lives (consumer behaviors). The nature of the relationships-comparison task and human cognitive processes is discussed.

Typicality or Fluency?

The modern Japanese writing system comprises different scripts, such as Kanji, Hiragana, and Katakana. These scripts differ greatly in both typicality and frequency of usage. In two experimental studies using names of cities or prefectures in Japan as target stimuli, we examined two hypotheses, the typicality hypothesis and fluency hypothesis, in order to assess effects of Japanese script on psychological processes. It was found that Kanji names induced typical thinking in a participant's description of a location, whereas Katakana names induced rather nontypical thinking. In contrast, we found that script differences did not affect distance estimations. We discuss these effects of Japanese script on psychological processes in terms of the typicality hypothesis (differences in typical usage habits between Kanji and Katakana that affect psychological processes).

Do People Explicitly Make a Frame Choice Based on the Reference Point?

Previous studies have shown that when choosing one of two logically equivalent frames (e.g., "half full" or "half empty"), people tend to choose based on a reference point. For example, when the amount of water in a glass with 500 ml capacity was originally 0 ml (or 500 ml), and then increased (or decreased) to 250 ml, people tend to express the amount of water in the glass as "half full" (or "half empty"). In the present study, we examined whether participants explicitly made a frame choice based on the reference point. We conducted four behavioral experiments relating to frame choice tasks. Specifically, participants were presented with a story-based or prime-based reference point and then made a frame choice. Furthermore, participants provided their reasons for the choice. Our findings on frame choices and their reasons can be summarized as follows. First, when participants were presented with a story-based reference point, some of them reported that they made frame choices based on the reference point. Second, when a reference point was presented as a prime, participants' frame choices were affected by this reference point. However, almost no participants reported that they made frame choices based on the reference point. These results indicate that the effect of reference points on frame choices is robust and that people do not always explicitly make frame choices based on the reference point.

Communicative functions of directional verbal probabilities: Speaker's choice, listener's inference, and reference points.

Verbal probabilities have directional communicative functions, and most can be categorized as positive (e.g., "it is likely") or negative (e.g., "it is doubtful"). We examined the communicative functions of verbal probabilities based on the reference point hypothesis According to this hypothesis, listeners are sensitive to and can infer a speaker's reference points based on the speaker's selected directionality. In four experiments (two of which examined speakers' choice of directionality and two of which examined listeners' inferences about a speaker's reference point), we found that listeners could make inferences about speakers' reference points based on the stated directionality of verbal probability. Thus, the directionality of verbal probabilities serves the communicative function of conveying information about a speaker's reference point.

Memory-Based Simple Heuristics as Attribute Substitution: Competitive Tests of Binary Choice Inference Models.

Some researchers on binary choice inference have argued that people make inferences based on simple heuristics, such as recognition, fluency, or familiarity. Others have argued that people make inferences based on available knowledge. To examine the boundary between heuristic and knowledge usage, we examine binary choice inference processes in terms of attribute substitution in heuristic use (Kahneman & Frederick, 2005). In this framework, it is predicted that people will rely on heuristic or knowledge-based inference depending on the subjective difficulty of the inference task. We conducted competitive tests of binary choice inference models representing simple heuristics (fluency and familiarity heuristics) and knowledge-based inference models. We found that a simple heuristic model (especially a familiarity heuristic model) explained inference patterns for subjectively difficult inference tasks, and that a knowledge-based inference model explained subjectively easy inference tasks. These results were consistent with the predictions of the attribute substitution framework. Issues on usage of simple heuristics and psychological processes are discussed.

On the role of rarity information in speakers' choice of frame.

In this article, we examine conversational behaviors when people describe the outcomes of uncertain events. We propose a new hypothesis, frame choice based on rarity information, that is built on the basis of one prominent measure of informativeness (i.e., self-information). The hypothesis predicts that when speakers can choose one of two logically equivalent frames for describing the outcome of an uncertain event (e.g., the results of the roll of a die or a medical operation), they prefer the frame denoting an event that is known or perceived to be rare. Four experiments using frame choice tasks provide evidence that speakers' choice of frame is explained well by the rarity hypothesis.

The role of familiarity in binary choice inferences.

In research on the recognition heuristic (Goldstein & Gigerenzer, Psychological Review, 109, 75-90, 2002), knowledge of recognized objects has been categorized as "recognized" or "unrecognized" without regard to the degree of familiarity of the recognized object. In the present article, we propose a new inference model--familiarity-based inference. We hypothesize that when subjective knowledge levels (familiarity) of recognized objects differ, the degree of familiarity of recognized objects will influence inferences. Specifically, people are predicted to infer that the more familiar object in a pair of two objects has a higher criterion value on the to-be-judged dimension. In two experiments, using a binary choice task, we examined inferences about populations in a pair of two cities. Results support predictions of familiarity-based inference. Participants inferred that the more familiar city in a pair was more populous. Statistical modeling showed that individual differences in familiarity-based inference lie in the sensitivity to differences in familiarity. In addition, we found that familiarity-based inference can be generally regarded as an ecologically rational inference. Furthermore, when cue knowledge about the inference criterion was available, participants made inferences based on the cue knowledge about population instead of familiarity. Implications of the role of familiarity in psychological processes are discussed.

Directional verbal probabilities: inconsistencies between preferential judgments and numerical meanings.

Verbal probability expressions (e.g., it is possible or doubtful) convey not only vague numerical meanings (i.e., probability) but also semantic functions, called directionality. We performed two experiments to examine whether preferential judgments are consistent with numerical meanings of verbal probabilities regardless of directionality. The results showed that because of the effects of directionality, perceived degrees of certainty for verbal probabilities differed between a binary choice and a numerical translation (Experiment 1), and decisions based on a verbal probability do not correspond to those based on a numerical translation for verbal probabilities (Experiment 2). These findings suggest that directionality of verbal probabilities is an independent feature from numerical meanings; hence numerical meanings of verbal probability alone remain insufficient to explain the effects of directionality on preferential judgments.

[Vagueness and the directionality of verbal probability expressions: the properties of probability information and their effects on decision making].

We examined the relationship between two properties of verbal probability (VP) expressions, "vagueness" and "directionality", and investigated the effects of these properties on decision making. Vagueness is defined as its imprecise characteristic of uncertainty expressions in VP, whereas the directionality is communicative functions which cause one to focus on the occurrence or non-occurrence of the target event described by VP. Experiment 1 contrasted a disagreement in the literature as to whether one can predict the directionality from vagueness properties, and our analyses resolved the conflict by showing the ineffectiveness of the vagueness in predicting the directionality. Experiment 2 administered decision tasks involving VP and numerical translation tasks of VP. We discovered that the directionality affects only on decision tasks. The results of Experiments 1 and 2 indicated that the directionality is distinct characteristic from the vagueness of VP, and these properties affect decisions independently. Implications are discussed.