Thursday, August 15, 2019

Empirical evidence for a statistically significant 4% gender wage gap among workers, at the project level; female workers propose lower wage bills and are more likely to win the competition for contracts, get higher revenues overall

Gomez Herrera, Estrella and Mueller-Langer, Frank, Is There a Gender Wage Gap in Online Labor Markets? Evidence from Over 250,000 Projects and 2.5 Million Wage Bill Proposals (July 9, 2019). Max Planck Institute for Innovation & Competition Research Paper No. 19-07. SSRN:

Abstract: We explore whether there is a gender wage gap in one of the largest EU online labor markets, PeoplePerHour. Our unique dataset consists of 257,111 digitally tradeable tasks of 55,824 hiring employers from 188 countries and 65,010 workers from 173 countries that made more than 2.5 million wage bill proposals in the competition for contracts. Our data allows us to track the complete hiring process from the employers' design of proposed contracts to the competition among workers and the final agreement between employers and successful candidates. Using Heckman and OLS estimation methods we provide empirical evidence for a statistically significant 4% gender wage gap among workers, at the project level. We also find that female workers propose lower wage bills and are more likely to win the competition for contracts. Once we include workers’ wage bill proposals in the regressions, the gender wage gap virtually disappears, i.e., it is statistically insignificant and very small in magnitude (0.3%). Our results also suggest that female workers’ higher winning probabilities associated with lower wage bill proposals lead to higher expected revenues overall. We provide empirical evidence for heterogeneity of the gender wage gap in some of the job categories, all job difficulty levels and some of the worker countries. Finally, for some subsamples we find a statistically significant but very small "reverse" gender wage gap.

Keywords: Gender wage gap, online labor markets, digitally performable projects
JEL Classification: D40; J40

The “unmotivated bias” of overprecision causes partisan hostility; prior literature has focused on motivated reasoning and social identity theory;overprecision increases hostility directly and indirectly

“Unmotivated bias” and partisan hostility: Empirical evidence. Daniel F. Stone. Journal of Behavioral and Experimental Economics, Volume 79, April 2019, Pages 12-26.

•    I argue that the “unmotivated bias” of overprecision causes partisan hostility.
•    Prior literature has focused on motivated reasoning and social identity theory.
•    I present evidence that overprecision increases hostility directly and indirectly.
•    The direct effects hold fixed ideology, partisanship, and motivated reasoning.
•    The indirect effects are via increasing strength of partisanship.

Abstract: Extreme partisan animosity has been on the rise in the US and is prevalent around the world. This hostility is typically attributed to social group identity, motivated reasoning, or a combination thereof. In this paper, I empirically examine a novel contributing factor: the “unmotivated” cognitive bias of overprecision (overconfidence in precision of beliefs). Overprecision could cause partisan hostility indirectly via inflated confidence in one’s own ideology, partisan identity, or perceptions of social distance between the parties. Overprecision could also cause this hostility directly by causing excessively strong inferences from observed information that is either skewed against the out-party or simply misunderstood. Using a nationally representative sample, I find consistent support for direct effects of overprecision and mixed support for indirect effects. The point estimates imply a one standard deviation increase in a respondent’s overprecision predicts as much as a 0.71 standard deviation decline in relative out-party favorability.

Dollars do not determine detection: Monetary value associated with unexpected objects does not affect the likelihood of inattentional blindness

Dollars do not determine detection: Monetary value associated with unexpected objects does not affect the likelihood of inattentional blindness. Dennis Redlich et al. Quarterly Journal of Experimental Psychology, March 18, 2019.

Abstract: Conscious perception often fails when an object appears unexpectedly and our attention is focused elsewhere (inattentional blindness). Although various factors have been identified that modulate the likelihood of this failure of awareness, it is not clear whether the monetary reward value associated with an object can affect whether or not this object is detected under conditions of inattention. We hypothesised that unexpectedly appearing objects that contain a feature linked to high value, as established via reward learning in a previous task, would subsequently be detected more frequently than objects containing a feature linked to low value. A total of 537 participants first learned the association between a perceptual feature (colour) and subsequent reward values (high, low, or none reward). Afterwards, participants were randomly assigned to a static (Experiment 1) or dynamic (Experiment 2) inattentional blindness task including an unexpected object associated with high, low, or none reward. However, no significant effect of the previously learned value on the subsequent likelihood of detection was observed. We speculate that artificial monetary value, which is known to affect attentional capture, is not strong enough to determine whether or not an object is consciously perceived.

Keywords: Failure of awareness, value-driven attention, inattentional blindness

Assessing the effects of vegetable consumption on the psychological health of healthy adults: a systematic review of prospective research

Assessing the effects of vegetable consumption on the psychological health of healthy adults: a systematic review of prospective research. Nicola-Jayne Tuck, Claire Farrow, Jason M Thomas. The American Journal of Clinical Nutrition, Volume 110, Issue 1, July 2019, Pages 196–211, June 1 2019,

Background: To alleviate the immense health and economic burden of mental illness, modifiable targets to promote psychological health are required. Emerging evidence suggests that both fruit and vegetable (F&V) consumption may play an important role. However, the precise contribution of vegetable consumption, which may represent a more potent target than the consumption of fruit, has received little attention.

Objectives: This review aimed to synthesize and evaluate research investigating the effects of vegetable consumption on mental health and psychological well-being in nonclinical, healthy adult populations. We aimed to provide insight into the causal relation between vegetable consumption and these outcomes.

Methods: Only studies with prospective or experimental data were included. The survey of the literature was last implemented on 1 February, 2019.

Results: Ten eligible studies were identified, with a total sample size of n = 33,645, that measured vegetable intake separately from fruit, or combined this with fruit intake. Where studies explored the independent effects of fruit and vegetable consumption on psychological health (n = 3), 2 reported a preferential effect of vegetables (compared with fruit) on psychological well-being, whereas 1 reported a superior effect of fruit intake on odds reduction of symptoms of depression. More broadly, there was evidence that consuming the recommended amount of F&V (and exceeding this) was associated with increased psychological well-being. However, the effects of F&V consumption on mental health symptoms were inconsistent.

Conclusions: Increased F&V consumption has a positive effect on psychological well-being and there appears to be a preferential effect of vegetables (compared with fruit) from the limited data examined. The effect of F&V intake on mental health is less clear and, at present, there are no clear data to support a preferential effect of vegetable intake on mental health outcomes. Hence, additional research is warranted to investigate the influence of vegetables, compared with fruit, on psychological health in order to inform nutrition-based interventions. This review was registered at as CRD42017072880.

Keywords: systematic review, vegetables, fruit, mental health, psychological well-being

Will Healthy Eating Make You Happier? A Research Synthesis Using an Online Findings Archive

Will Healthy Eating Make You Happier? A Research Synthesis Using an Online Findings Archive. Ruut Veenhoven. Applied Research in Quality of Life, August 14 2019.

Abstract: Healthy eating adds to health and thereby contributes to a longer life, but will it also add to a happier life? Some people do not like healthy food, and since we spend a considerable amount of our life eating, healthy eating could make their life less enjoyable. Is there such a trade-off between healthy eating and happiness? Or instead a trade-on, healthy eating adding to happiness? Or do the positive and negative effects balance? If there is an effect of healthy eating on happiness, is that effect similar for everybody? If not, what kind of people profit from healthy eating happiness wise and what kind of people do not? If healthy eating does add to happiness, does it add linearly or is there some optimum for healthy ingredients in one’s diet? I considered the results published in 20 research reports on the relation between nutrition and happiness, which together yielded 47 findings. I reviewed these findings, using a new technique. The findings were entered in an online ‘findings archive’, the World Database of Happiness, each described in a standardized format on a separate ‘findings page’ with a unique internet address. In this paper, I use links to these finding pages and this allows us to summarize the main trends in the findings in a few tabular schemes. Together, the findings provide strong evidence of a causal effect of healthy eating on happiness. Surprisingly, this effect is not fully mediated by better health. This pattern seems to be universal, the available studies show only minor variations across people, times and places. More than three portions of fruits and vegetables per day goes with the most happiness, how many more for what kind of persons is not yet established.

Keywords: Happiness Health behaviour Diet Research synthesis

The Pot Rush: Is Legalized Marijuana A Positive Local Amenity?

The Pot Rush: Is Legalized Marijuana A Positive Local Amenity? Diego Zambiasi  Steven Stillman. Economic Inquiry, August 14 2019.

Abstract: This paper examines the amenity value of legalized marijuana by analyzing the impact of marijuana legalization on migration to Colorado. Colorado is the pioneering state in this area having legalized medical marijuana in 2000 and recreational marijuana in 2012. We test whether potential migrants to Colorado view legalized marijuana as a positive or negative local amenity. We use the synthetic control methodology to examine in‐ and out‐migration to/from Colorado versus migration to/from counterfactual versions of Colorado that have not legalized marijuana. We find strong evidence that potential migrants view legalized marijuana as a positive amenity with in‐migration significantly higher in Colorado compared with synthetic‐Colorado after the writing of the Ogden memo in 2009 that effectively allowed state laws already in place to be activated, and additionally after marijuana was legalized in 2013 for recreational use. When we employ permutation methods to assess the statistical likelihood of our results given our sample, we find that Colorado is a clear and significant outlier. We find no evidence for changes in out‐migration from Colorado suggesting that marijuana legalization did not change the equilibrium for individuals already living in the state.

Extraversion: The most important trait in sexual behavior (number of lifetime sexual partners, involvement in casual sex, marital infidelity, condom use, sexual coercion, & sexual harassment)

The Role of Personality in Sexual and Reproductive Health. Mark S. Allen. Current Directions in Psychological Science, August 14, 2019.

Abstract: Strong evidence suggests that sexual behavior and reproductive success can be predicted by personality traits. Here, I review new studies that have contributed to the understanding of these associations and outline potential avenues for further research. Findings show that extraversion is the most important personality trait in sexual behavior (number of lifetime sexual partners, involvement in casual sex, marital infidelity, condom use, male and female sexual dysfunction, sexual coercion, and sexual harassment) and that neuroticism, agreeableness, and conscientiousness are also associated with these outcomes. Extraversion has emerged as the most important personality trait for fertility in men but appears relatively unimportant for fertility in women. Findings for other personality traits are somewhat mixed, probably because of variations in research design, and further prospective studies are recommended to address potential bidirectional associations. Further research is also needed in adolescent samples, in understudied topic areas (e.g., sexually transmitted infections, biomarkers of fertility), and on personality similarity between sexual partners in samples from both poor and developed nations.

Keywords: five-factor model, fecundity, infertility, sexuality, sexually transmitted infections

After having used a catalyst (flipping a coin) to make a decision, we experience a stronger feeling of suddenly knowing what we want, even when discarding the suggestion of the decision aid

Jaffé ME, Reutner L, Greifeneder R (2019) Catalyzing decisions: How a coin flip strengthens affective reactions. PLoS One 14(8): e0220736, August 14, 2019.

Abstract: When individuals are undecided between options, they may flip a coin or use other aids that produce random outcomes to support decision-making. Such aids lead to clear suggestions, which, interestingly, individuals do not necessarily follow. Instead when looking at the outcome, individuals sometimes appear to like or dislike the suggestion, and then decide according to this feeling. In this manuscript we argue that such a decision aid can function as a catalyst. As it points to one option over the other, individuals focus on obtaining this option and engage in a more vivid representation of the same. By imagining obtaining the option, feelings related to the option become stronger, which then drive feelings of satisfaction or dissatisfaction with the outcome of the decision aid. We provide support for this phenomenon throughout two studies. Study 1 indicates that using a catalyst leads to stronger feelings. Study 2 replicates this finding using a different catalyst, and rules out alternative explanations. Here, participants report that after having used a catalyst, they experienced a stronger feeling of suddenly knowing what they want compared to the control group that did not use a catalyst. Implications of these results for research and practice are discussed.