Judgments in the Sharing Economy: The Effect of User-Generated Trust and Reputation Information on Decision-Making Accuracy and Bias.

The growing ecosystem of peer-to-peer enterprise - the Sharing Economy (SE) - has brought with it a substantial change in how we access and provide goods and services. Within the SE, individuals make decisions based mainly on user-generated trust and reputation information (TRI). Recent research indicates that the use of such information tends to produce a positivity bias in the perceived trustworthiness of fellow users. Across two experimental studies performed on an artificial SE accommodation platform, we test whether users' judgments can be accurate when presented with diagnostic information relating to the quality of the profiles they see or if these overly positive perceptions persist. In study 1, we find that users are quite accurate overall (70%) at determining the quality of a profile, both when presented with full profiles or with profiles where they selected three TRI elements they considered useful for their decision-making. However, users tended to exhibit an "upward quality bias" when making errors. In study 2, we leveraged patterns of frequently vs. infrequently selected TRI elements to understand whether users have insights into which are more diagnostic and find that presenting frequently selected TRI elements improved users' accuracy. Overall, our studies demonstrate that - positivity bias notwithstanding - users can be remarkably accurate in their online SE judgments.

Behavioral Fatigue: Real Phenomenon, Naïve Construct, or Policy Contrivance?

In some countries, government policies to combat Covid-19 have been based on the notion that behavioral fatigue prevents people maintaining self-isolation and other restrictions to their life styles for more than a short time. By 16 March 2020, 681 United Kingdom behavioral scientists had signed an open letter to their government asking it to reveal the evidence that shows that behavioral fatigue exists. Nothing was forthcoming. The provenance of concept remains a mystery but modelers have argued that the delay in implementing lockdown policies, for which it was at least partly responsible, led to the loss of at least 20,000 lives. Here, I consider whether behavioral fatigue is a real phenomenon by assessing (a) direct evidence consistent and inconsistent with its existence and (b) indirect evidence drawn from other domains. I conclude that evidence for it is not sufficient to constrain policy. It is reasonable to conclude that behavioral fatigue is either a naïve construct or a myth that arose during the development of policy designed to tackle the Covid-19 crisis.

Digital Identity: The effect of trust and reputation information on user judgement in the Sharing Economy.

The Sharing Economy (SE) is a growing ecosystem focusing on peer-to-peer enterprise. In the SE the information available to assist individuals (users) in making decisions focuses predominantly on community-generated trust and reputation information. However, how such information impacts user judgement is still being understood. To explore such effects, we constructed an artificial SE accommodation platform where we varied the elements related to hosts' digital identity, measuring users' perceptions and decisions to interact. Across three studies, we find that trust and reputation information increases not only the users' perceived trustworthiness, credibility, and sociability of hosts, but also the propensity to rent a private room in their home. This effect is seen when providing users both with complete profiles and profiles with partial user-selected information. Closer investigations reveal that three elements relating to the host's digital identity are sufficient to produce such positive perceptions and increased rental decisions, regardless of which three elements are presented. Our findings have relevant implications for human judgment and privacy in the SE, and question its current culture of ever increasing information-sharing.

Task complexity moderates the influence of descriptions in decisions from experience.

Decisions-makers often have access to a combination of descriptive and experiential information, but limited research so far has explored decisions made using both. Three experiments explore the relationship between task complexity and the influence of descriptions. We show that in simple experience-based decision-making tasks, providing congruent descriptions has little influence on task performance in comparison to experience alone without descriptions, since learning via experience is relatively easy. In more complex tasks, which are slower and more demanding to learn experientially, descriptions have stronger influence and help participants identify their preferred choices. However, when the task gets too complex to be concisely described, the influence of descriptions is reduced hence showing a non-monotonic pattern of influence of descriptions according to task complexity. We also propose a cognitive model that incorporates descriptive information into the traditional reinforcement learning framework, with the impact of descriptions moderated by task complexity. This model fits the observed behavior better than previous models and replicates the observed non-monotonic relationship between impact of descriptions and task complexity. This research has implications for the development of effective warning labels that rely on simple descriptive information to trigger safer behavior in complex environments.

Assessing Risk in Graphically Presented Financial Series.

It has been argued that traders use their natural sensitivity to the fractal properties of price graphs to assess risk and that they are better able to do this when given price change as well as price level information. This approach implies that risk assessments should be higher when the Hurst exponents are lower, that this relationship should be stronger in the presence of price change information and that risk assessment should depend more strongly on the Hurst exponent than on the standard deviation of the series. Participants in Experiment 1 decided which of two assets was riskier by inspecting graphs of their price series. Graphs with lower Hurst exponents were selected only by those who were less emotionally stable and hence more sensitive to risk. However, when both price series and price change series were presented, the assets with lower Hurst exponents were selected by all participants. In a second experiment, participants were given both price level and price change series for a number of assets and rated the risk of trading in each one. Ratings depended more strongly on Hurst exponents than on other measures of volatility. They also depended on indicators of potential loss. Human risk assessment deviates from the way that risk is measured in modern finance theory: it requires integration of information relevant to both uncertainty and loss aversion, thereby imposing high attentional demands on traders. These demands may impair risk assessment but they can be eased by adding displays of price change information.

Carry on winning: no selection effect.

The methods proposed by Demaree, Weaver and Juergensen (2014) are not the most appropriate for testing for the presence of a selection effect. We use a simple and straightforward method to demonstrate that the data are not consistent with such an effect.

Carry on winning: the gamblers' fallacy creates hot hand effects in online gambling.

People suffering from the hot-hand fallacy unreasonably expect winning streaks to continue whereas those suffering from the gamblers' fallacy unreasonably expect losing streaks to reverse. We took 565,915 sports bets made by 776 online gamblers in 2010 and analyzed all winning and losing streaks up to a maximum length of six. People who won were more likely to win again (apparently because they chose safer odds than before) whereas those who lost were more likely to lose again (apparently because they chose riskier odds than before). However, selection of safer odds after winning and riskier ones after losing indicates that online sports gamblers expected their luck to reverse: they suffered from the gamblers' fallacy. By believing in the gamblers' fallacy, they created their own hot hands.

Depletable resources: necessary, in need of fair treatment, and multi-functional.

I make three points. First, processors and depletable resources should not be regarded as alternative means of processing information: they are both necessary. Second, comparing a processor account with a rational allocation mechanism to a depletable-resources account without one is not a fair comparison. Third, depletable resources can act as signals as well as fuels.

Trend damping: Under-adjustment, experimental artifact, or adaptation to features of the natural environment?

People's forecasts from time series underestimate future values for upward trends and overestimate them for downward ones. This trend damping may occur because (a) people anchor on the last data point and make insufficient adjustment to take the trend into account, (b) they adjust toward the average of the trends they have encountered within the experiment, or (c) they are adapted to an environment in which natural trends tend to be damped. Two experiments eliminated the first account: For series that are negatively accelerated or have shallow slopes, people showed anti-damping (the opposite of damping), a phenomenon that cannot be interpreted in terms of under-adjustment. These experiments also produced results consistent with the second account: Forecasts for a given function clearly depended on the other functions that were forecast within the same experiment. However, this second account was itself eliminated by a third experiment demonstrating both damping and, to a lesser degree, anti-damping when people forecast from a single series. We conclude that people have adapted to degrees of growth and decay that are representative of their environment: Damping occurs when trends in presented series are steeper than this and anti-damping occurs when they are shallower.

Effects of shopping addiction on consumer decision-making: Web-based studies in real time.

Background and aims Most research into compulsive buying has focused on its causes: questionnaires have been used to study its association with various factors assumed to be important in its etiology. Few studies have dealt with the effects of being a compulsive buyer on shopping decisions. Also, processes underlying compulsive buying are dynamic but questionnaires give access only to a retrospective view of them from the standpoint of the participant. The aim of the current study was to investigate the decision processes underlying compulsive buying. Methods Two simulated shopping experiments, each with over 100 participants, were used to compare the decision processes of compulsive shoppers with those of non-compulsive shoppers. This approach allowed us to measure many features of consumer decision-making that are relevant to compulsive shopping. Results Compulsive shoppers differed from general shoppers in six ways: choice characteristics, searching behavior, overspending, budget-consciousness, effects of credit card availability, and emotional responses to overspending. Conclusions Results are consistent with the view that compulsive buying, like other behavioral addictions, develops because the cognitive system under-predicts the extent of post-addiction craving produced by emotional and visceral processes.

The impact of discredited evidence.

How do people revise their beliefs when evidence is discredited? In three studies, mock jurors read simplified criminal cases and then judged the probability that a suspect was guilty on the basis of sequentially presented evidence. Study 1 showed an extension effect: When two items of incriminating evidence were presented, a subsequent discrediting of the second item also lessened belief in the first item, irrespective of whether it was directly related to the discredited item. Study 2 showed that this effect depended on the order of evidence presentation: When the discrediting evidence was presented early, rather than late, in the sequence, there was no extension to unrelated items. Study 3 showed that the extension effect held only when items of evidence were both incriminating or both exonerating, but not when they were mixed. To explain these findings, we draw on coherence-based models of juror reasoning and propose that people group evidence according to its direction with respect to the guilt hypothesis.

Biased forecasting of postdecisional affect.

Although anticipated postdecisional regret is a significant contributor to people's decision-making processes, the accuracy of people's regret forecasts has yet to be assessed systematically. Here we report two studies to fill this lacuna. In Study 1, we found that subjects who made reasonably high offers overpredicted the regret that they experienced after they unexpectedly failed at a negotiation. In Study 2, we found that subjects overpredicted the rejoicing and marginally underpredicted the regret that they experienced when they received higher marks than they had expected for their course work. Systematic affective misprediction implies that people making decisions should discount the regret and rejoicing that they anticipate will be associated with potential outcomes arising from those decisions.

Which doctors are influenced by a patient's age? A multi-method study of angina treatment in general practice, cardiology and gerontology.

BACKGROUND: Elderly patients with cardiovascular disease are relatively undertreated and undertested. OBJECTIVES: To investigate whether, and how, individual doctors are influenced by a patient's age in their investigation and treatment of angina. DESIGN: Process-based judgment analysis using electronic patients, semistructured interviews. SETTING: Primary Care, Care of the Elderly and Cardiology in England. PARTICIPANTS: Eighty five doctors: 29 cardiologists, 28 care of the elderly specialists and 28 general practitioners (GPs). MAIN OUTCOME MEASURES: Testing and treatment decisions on hypothetical patients. RESULTS: Forty six per cent of GPs and care of the elderly doctors, and 48% of cardiologists treated patients aged 65+ differently to those under 65, independent of comorbidity. This effect was evident on several decisions: elderly patients were less likely to be prescribed a statin given a cholesterol test, referred to a cardiologist, given an exercise tolerance test, angiography and revascularisation; more likely to have their current prescriptions changed and to be given a follow-up appointment. There was no effect of specialty, gender or years of training on influence of patient age. Those doctors who were influenced by age were on average five years older than those who were not. Interviews revealed that some doctors saw old age as a contraindication to treat. CONCLUSIONS: Age, independent of comorbidity, presentation and patients' wishes, directly influenced decision-making about angina investigation and treatment by half of the doctors in the primary and secondary care samples. Doctors explicitly reasoned about the direct influence of age and age-associated influences.

Predicting preferences: a neglected aspect of shared decision-making.

In recent years, shared decision-making between patients and doctors regarding choice of treatment has become an issue of priority. Although patients' preferences lie at the core of the literature on shared decision-making, there has not been any attempt so far to link the concept of shared decision-making with the extensive behavioural literature on people's self-predictions of their future preferences. The aim of the present review is to provide this link. First, we summarize behavioural research that suggests that people mispredict their future preferences and feelings. Secondly, we provide the main psychological accounts for people's mispredictions. Thirdly, we suggest three main empirical questions for inclusion in a programme aimed at enriching our understanding of shared decision-making and improving the procedures used for putting it into practice.

Variations in cardiac interventions: doctors' practices and views.

OBJECTIVES: To investigate referral rates for cardiac interventions by clinical specialty, to document doctors' reasons for referrals and to explore doctors' perceptions of the factors that influenced their clinical decisions. STUDY DESIGN: Doctors completed a clinical decision-making exercise involving, in total, 6093 electronic patients with cardiac disease, and subsequently took part in the semi-structured interviews about influences on their decisions. Interviews were audio-recorded, transcribed and coded using a thematic approach, with the coding categories derived from the data. STUDY SETTING: Eighty-eight doctors (GPs, care-of-the-elderly specialists, cardiologists) participated in the full study, in seven areas in southern, central and northern England. Complete interview data were analysed for 76 of these. PRINCIPAL FINDINGS: Not all patients who were eligible for specific investigations or treatment received these. The extent of variations in clinical decisions differed by type of intervention. Apart from the general reasons for referrals, doctors raised nine main influences on their actual decision making. The most commonly reported influence ('barrier') was poor access to equipment for intervention, which increased thresholds for investigation and treatment. CONCLUSIONS: The current emphasis on achieving targets in the British NHS has led to a focus on easily measurable, but crude, process targets such as waiting lists. This study points to the need to include a broader quality assurance element to investigate the cluster of system failures which lead to variations in clinical decisions and thereby to inequitable treatment.

Regret triggers inaction inertia--but which regret and how?

When people miss a good bargain, they are less likely to take a subsequent one that is not as good. This phenomenon is termed inaction inertia. Two regret-based explanations of it have been proposed. According to one, people anticipate that buying the item will lead to regret because it will remind them that they missed a better opportunity to buy it. According to the other, the regret people experience when missing a bargain, together with a subjective devaluation of the item resulting from that, produces inaction inertia. In two studies, we assessed experienced regret, anticipated regret, subjective valuation (SV) of the bargain and likelihood of purchase. Our findings provide grounds for reconciling the above accounts. The former is more appropriate when the difference between the previous and subsequent bargain is large, and the latter is more appropriate when it is smaller. Furthermore, our findings suggest that previous accounts of inaction inertia are incomplete. Whereas subjective value and regret considerations jointly determine purchase likelihood when no previous opportunity has been missed, regret considerations are the sole determinant of this likelihood when such an opportunity has been missed. Inaction inertia arises at least partly because considering regret turns attention away from the financial advantages of taking the bargain.

Assessing the likelihood of an important clinical outcome: new insights from a comparison of clinical and actuarial judgment.

PURPOSE: To assess and rank the performance of different methods of predicting the probability of death following a specified surgical procedure. METHOD: Actuarial estimates of the probability of early mortality for 40 patients were derived from 2 sources: a large published surgical series and a smaller series from the center where surgery was performed. Surgeons and cardiologists also provided probability estimates for these patients. RESULTS: Estimates derived from the published literature were too optimistic and did not differentiate between patients more, or less, likely to die (i.e., failed to discriminate). Doctors' judgments were unbiased but failed to discriminate. Local actuarial estimates (influenced by only 1 or 2 variables) were unbiased, did discriminate, but exhibited more random variation. CONCLUSIONS: The preferred source of estimates depends upon which aspect of accuracy is of greatest importance. Differences in patient selection and error in the identification of risk factors mean that published results will not always appropriately predict surgical risk at other institutions. Risk stratification may be more robust when based on a small set of cross-validated predictors rather than a larger set of predictors that includes some whose reliability has not been confirmed.