The Impact of Variation in Twin Relatedness on Estimates of Heritability and Environmental Influences. Chang Liu, Peter C. M. Molenaar, and Jenae M. Neiderhiser. Behavior Genetics, https://link.springer.com/article/10.1007/s10519-017-9875-x
Abstract: By taking advantage of the natural variation in genetic relatedness among identical (monozygotic: MZ) and fraternal (dizygotic: DZ) twins, twin studies are able to estimate genetic and environmental contributions to complex human behaviors. Recently concerns have been raised about the accuracy of twin studies in light of findings of genetic and epigenetic changes in twins. One of the concerns raised is that MZ twins are not 100% genetically and epigenetically similar because they show variations in their genomes and epigenomes leading to inaccurate estimates of heritability. This article presents findings from a simulation study that examined the degree of bias in estimates of heritability and environmentality when the genetic and epigenetic similarity of MZ twins differs from 1.00 and when the genetic and epigenetic similarity of DZ twins differs from 0.50. The findings suggest that in the standard biometric model when MZ or DZ twin similarity differs from 1.00 or 0.50, respectively, the variance that should be attributed to genetic influences is instead attributed to nonshared environmental influences, thus deflating the estimates of genetic influences and inflating the estimates of nonshared environmental influences. Although estimates of genetic and nonshared environmental influences from the standard biometric model were found to deviate from “true” values, the bias was usually smaller than 10% points indicating that the interpretations of findings from previous twin studies are mostly correct.
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Thursday, November 2, 2017
Sex Differences in the Prevalence and Correlates of Handgun Carrying Among Adolescents in the USA
Sex Differences in the Prevalence and Correlates of Handgun Carrying Among Adolescents in the United States. Michael G. Vaughn et al. Youth Violence and Juvenile Justice, https://doi.org/10.1177/1541204017739072
Abstract: Handgun carrying is associated with a wide range of delinquent behaviors, but very little is known about sex differences in this behavior and current trends in handgun carrying in the United States. Using data from the 2002 to 2015 National Study of Drug Use and Health surveys, we found that the prevalence of handgun carrying among girls nearly doubled from 0.9% to 1.7% with most of this increase seen among non-Hispanic White and Hispanic girls. Although boys are more likely to carry handguns, approximately 20% of the total handgun carrying by adolescents in the United States occurs among girls. Both male and female adolescents who have carried a handgun in the past year evince a behavioral profile that is characterized by substance use, versatile delinquency, elevated risk propensity, and substantial school and family problems. However, adjusted odds ratios are consistently higher for females, suggesting that girls who engage in handgun carrying represent an important subgroup of potentially pernicious offenders that should be targeted for primary and tertiary prevention and juvenile justice system oversight.
Abstract: Handgun carrying is associated with a wide range of delinquent behaviors, but very little is known about sex differences in this behavior and current trends in handgun carrying in the United States. Using data from the 2002 to 2015 National Study of Drug Use and Health surveys, we found that the prevalence of handgun carrying among girls nearly doubled from 0.9% to 1.7% with most of this increase seen among non-Hispanic White and Hispanic girls. Although boys are more likely to carry handguns, approximately 20% of the total handgun carrying by adolescents in the United States occurs among girls. Both male and female adolescents who have carried a handgun in the past year evince a behavioral profile that is characterized by substance use, versatile delinquency, elevated risk propensity, and substantial school and family problems. However, adjusted odds ratios are consistently higher for females, suggesting that girls who engage in handgun carrying represent an important subgroup of potentially pernicious offenders that should be targeted for primary and tertiary prevention and juvenile justice system oversight.
Evidence of the Effect of Confirmation-Reports on Dishonesty
Duncan, D. and Li, D. (2017), Liar Liar: Experimental Evidence of the Effect of Confirmation-Reports on Dishonesty. Southern Economic Journal. doi:10.1002/soej.12244
Abstract: We identify the effect of confirmation-reports on dishonesty using data from an experiment where subjects are asked to roll a die and report its outcome using either a self-report or confirmation-report mechanism. We find that relative to self-reports, confirmation-reports have a positive effect on the share of subjects who report honestly. The effect on the magnitude of lies told depends greatly on the accuracy of the prefilled information on the confirmation-report. We argue that these results are driven by changes in the intrinsic costs of lying induced by the confirmation report.
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Obviously, men lie more than women in both conditions.
Abstract: We identify the effect of confirmation-reports on dishonesty using data from an experiment where subjects are asked to roll a die and report its outcome using either a self-report or confirmation-report mechanism. We find that relative to self-reports, confirmation-reports have a positive effect on the share of subjects who report honestly. The effect on the magnitude of lies told depends greatly on the accuracy of the prefilled information on the confirmation-report. We argue that these results are driven by changes in the intrinsic costs of lying induced by the confirmation report.
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Obviously, men lie more than women in both conditions.