Base rate neglect for the wealth of populations

Base rate neglect has been shown to be a very robust bias in human information processing. It has also been show to be ecologically rational in some environments. However, when arguing about base rate neglect usually isolated individuals are considered. I complement these results by showing that in many scenarios of social learning a base rate neglect increases a population's wealth. I thereby strengthen the argument that the presence of base rate neglect could be evolutionary stable. I pick up a model of social learning that has been used to demonstrate the potential benefits of overconfidence. Individuals are confronted with a safe and a risky option. They receive a private signal about the risky option's outcome, they decide in an exogenously given sequence, and they observe decisions of preceding individuals. I first deviate from the original model by incorporating base rates that differ from fifty-fifty and show that under weighting this base rate can be for the wealth of a population. Then I analyse how the optimal base rate neglect reacts to changes in payoffs. I show that for large set of settings under weighting the base rate is still positive, but for a smaller subset it decreases wealth insteadcognitive biases, base rate neglect, social learning, ecological rationality

Attitude Dynamics with Limited Verbalisation Capabilities

This article offers a new perspective for research on opinion dynamics. It demonstrates the importance of the distinction of opinion and attitude, which originally has been discussed in literature on consumer behaviour. As opinions are verbalised attitudes not only biases in interpretation and adoption processes have to be considered but also verbalisation biases should be addressed. Such biases can be caused by language deficits or social norms. The model presented in this article captures the basic features of common opinion dynamic models and additionally biases in the verbalisation process. Further, it gives a first analysis of this model and shows that precision as bias in the verbalisation process can influence the dynamics significantly. Presenting and applying the concept of area of influential attitudes the impact of each parameter (selective attitude, selective interpretation, and precision) is analysed independently. Some preliminary results for combined effects are presented.Opinion dynamics, attitude dynamics, verbalisation, selective attitude, selective interpretation, area of influential attitudes

The structure of optimism : "Controllability affects the extent to which efficacy beliefs shape outcome expectancies"

In this article we theoretically develop and empirically test an integrative conceptual framework linking dispositional optimism as general outcome expectancy to general efficacy beliefs about internal (self) and external (instrumental social support and chance) factors as well as to general control beliefs (locus-of-control). Bandura (1997, Self-efficacy. The exercise of control (p. 23). New York: Freeman), quoted in title, suggests – at a context-specific level – that controllability moderates the impact of self-efficacy on outcome expectancies and we hypothesize that – at a general level – this also applies to dispositional optimism. We further hypothesize that locus of control moderates the impact of external-efficacy beliefs, but in the opposite direction as self-efficacy. Our survey data of 224 university students provides support for the moderation of self-efficacy and chance-efficacy. Our new conceptualization contributes to clarifying relationships between self- and external-efficacy beliefs, control beliefs, and optimism; and helps to explain why equally optimistic individuals cope very differently with adverse situations

Opinion Dynamics: the Effect of the Number of Peers Met at Once

The opinion dynamics model introduced by Deffuant and Weisbuch as well as the one by Hegselmann and Krause are rather similar. In both models individuals are assumed to have opinions about an issue, they meet and discuss, and they may adapt their opinions towards the other agents` opinions or may ignore each other if their positions are too different. Both models differ with respect to the number of peers they meet at once. Furthermore the model by Deffuant and Weisbuch has a convergence parameter that controls how fast agents adapt their opinions. By defining the reversed parameter as self-support we can extend the applicability of this parameter to scenarios with more than one interaction partner. We investigate the effects of changing the number of peers met at once, which is done for different population sizes, and the effects of changing the self-support. For describing the dynamics we look at different statistics, i.e. number of cluster, number of major clusters, and Gini coefficient.Opinion Dynamics, Communication Regime

What is your level of overconfidence? A strictly incentive compatible measurement of absolute and relative overconfidence.

This study contributes to the ongoing discussion on the appropriate measurement of overconfidence, in particular, its strictly incentive compatible measurement in experiments. Despite a number of significant advances in recent research, several important issues remain to be solved. These relate to the strictness of incentive compatibility, the identification of well-calibrated participants, the trichotomous classification into over- or underconfident and well-calibrated participants, and the generalization to measuring beliefs about the performance relative to other people. This paper develops a measurement of overconfidence that is improved regarding all four of these issues. We theoretically prove that our method is strictly incentive compatible and robust to risk attitudes within the framework of Cumulative Prospect Theory. Furthermore, our method allows the measurement of various levels of overconfidence and the direct comparison of absolute and relative confidence. We tested our method, and the results meet our expectations, replicate recent results, and show that a population can be simultaneously overconfident, well-calibrated, and underconfident. In our specific case, we find that more than ninety-five percent of the population believe to be better than twenty-five percent; about fifty percent believe to be better than fifty percent; and only seven percent believe to be better than seventy-five percent.Belief elicitation, Overconfidence, Better than average, Incentive compatibility

A short measure of four types of personal optimism: ability, rivalry, chance, and social support (ARCS)

Self-efficacy, which can be defined as optimism about ones own ability to exercise required actions, has received a lot of attention in research on entrepreneurs and managers decision making. This attention led to the development of corresponding measurement instruments. However, there is no equivalent measure of the more general personal optimism that jointly captures on equivalent bases abilities and other sources of uncertainty, which one might be more or less optimistic about. I develop a measurement instrument of four dimensions of personal optimism: ability optimism (self-efficacy), rivalry optimism (being better than others), chance optimism (being a lucky devil or fearing of bad-luck), and social support optimism (others help and support me and are trustworthy). Correlations between subscales are intuitive and backed by theory. I replicate corresponding results from previous studies that used different measures, e.g. life-orientation (LOT-R), self-efficacy (NGSE), and social optimism at the societal level from the POSO scale. This new personal optimism measurement instrument is very much like the life-orientation test (LOT-R), but it provides more insights regarding the structure of optimism. Whenever self-efficacy or control beliefs are of interest, the ARCS or ACS scales should be used to control for complementary world beliefs. I also illustrate the special role of one item in NGSE, which in contrast to all other NGSE items refers to a comparative instead of an absolute judgment

Optimistic, but not in control: Life-orientation and the theory of mixed control

Why are some people more optimistic about their life than others? Literature on locus of control suggests that optimism is associated with the belief that one's life outcomes are controlled by internal factors, such as ability, instead of external factors, such as powerful others or chance. Furthermore, some authors suggest that internal control beliefs interact with self-efficacy beliefs regarding their effects on outcome expectancies and thus optimism. We argue that it is not only self-efficacy that interacts, but efficacy beliefs about external factors, too. We further hypothesize that the effect of perceiving internal rather than external control on dispositional optimism depends on the difference between efficacy beliefs regarding internal and external factors. Since people can influence other people to be helpful, i.e., take proxy control, but are unlikely to influence chance, we extend this internal-versus-external view and suggest that the difference between perceived control by others and perceived control by chance affect dispositional optimism. In fact, we hypothesize that the effect of perceiving that it is other people who are in control, rather than chance, depends on the difference between efficacy beliefs regarding others and chance. A first empirical survey-based test produces substantial support for our theory. This is the first time control-efficacy interaction effects are shown for dispositional variables and for the three-dimensional construct of locus of control. We replicate a gender effect on correlations of dispositional optimism with self-reported risk taking and observe a gender effect for one of our new hypotheses

Exploiting opportunities at all cost? Entrepreneurial intent and externalities

Do potential entrepreneurs exploit welfare-destroying opportunities as much as they exploit welfare-enhancing opportunities as it is assumed in several normative models? Do we need to prevent potential entrepreneurs from being destructive or are there intrinsic limits to harm others? We experimentally investigate how people with different entrepreneurial intent exploit risky investment opportunities that are associated with negative and positive externalities. We find that participants who consider entrepreneurship as a future occupation invest significantly less than others in destructive opportunities. Nevertheless, our results support prior evidence that the entrepreneurially talented invest more in destructive opportunities. The latter effect seems to be entrepreneurship-specific, because the investment behavior of the generally more talented does not differ from that of other participants. Taken together, our results suggest that people who are willing to exploit destructive opportunities do not only do this in private ventures, but also - and maybe even more so - in wage employment.Social Psychology, Entrepreneurship, Externalities, Laboratory, Individual Behavior

Economics meets psychology: Experimental and self-reported measures of individual competitiveness

Economists and psychologists follow different approaches to measure individual competitiveness. While psychologists typically use self-reported psychometric scales, economists tend to use incentivized behavioral experiments, where subjects confronted with a specific task self-select into a competitive versus a piece-rate payment scheme. So far, both measurement approaches have remained largely isolated from one another. We discuss how these approaches are linked and based on a classroom experiment with 186 students we empirically examine the relationship between a behavioral competitiveness measure and a self-reported competitiveness scale. We find a stable positive relationship between these measures suggesting that both measures are indicators of the same underlying latent variable, which might be interpreted as a general preference to enter competitive situations. Moreover, our results suggest that the self-reported scale partly rests on motives related to personal development, whereas the behavioral measure does not reflect competitiveness motivated by personal development. Our study demonstrates how comparative studies such as ours can open up new avenues for the further development of both behavioral experiments andpsychometric scales that aim at measuring individual competitiveness