Confidence biases and learning among intuitive Bayesians

We design a double-or-quits game to compare the speed of learning one’s specific ability with the speed of rising confidence as the task gets increasingly difficult. We find that people on average learn to be overconfident faster than they learn their true ability and we present an intuitive-Bayesian model of confidence which integrates confidence biases and learning. Uncertainty about one’s true ability to perform a task in isolation can be responsible for large and stable confidence biases, namely limited discrimination, the hard–easy effect, the Dunning–Kruger effect, conservative learning from experience and the overprecision phenomenon (without underprecision) if subjects act as Bayesian learners who rely only on sequentially perceived performance cues and contrarian illusory signals induced by doubt. Moreover, these biases are likely to persist since the Bayesian aggregation of past information consolidates the accumulation of errors and the perception of contrarian illusory signals generates conservatism and under-reaction to events. Taken together, these two features may explain why intuitive Bayesians make systematically wrong predictions of their own performance.     

Pair‐copula constructions for non‐Gaussian DAG models

We propose a new type of multivariate statistical model that permits non‐Gaussian distributions as well as the inclusion of conditional independence assumptions specified by a directed acyclic graph. These models feature a specific factorisation of the likelihood that is based on pair‐copula constructions and hence involves only univariate distributions and bivariate copulas, of which some may be conditional. We demonstrate maximum‐likelihood estimation of the parameters of such models and compare them to various competing models from the literature. A simulation study investigates the effects of model misspecification and highlights the need for non‐Gaussian conditional independence models. The proposed methods are finally applied to modeling financial return data. The Canadian Journal of Statistics 40: 86–109; 2012 © 2012 Statistical Society of Canada     

Registration,Residency Restrictions,and Community Notification: A Social Capital Perspective on the Isolation of Registered Sex Offenders in Our Communities

This article highlights the importance of social capital for registered sex offenders who are reintegrating back into their communities. Although not always identified among community corrections, the sex offender registry creates a punitive atmosphere that diminishes the amount of available social capital for all involved—community members, sex offenders, and the government. Lost social capital contributes to recidivism, reentry problems, and mental health issues among registered sex offenders. We argue that deterrent and protective features of the sex offender registry are overemphasized and the goal of reintegration has been undermined. The loss of social capital exacerbates (1) the minimization of trust, (2) low expectations of rehabilitation and reentry, (3) limited contact and information from role models, (4) increased access to criminal capital, (5) formal sanctioning power of the registry, and (6) loss of sanctioning power from family and communities. Through this in-depth analysis, we argue that the current state of the registry system harms the social capital of all involved when a sex offense occurs—not just the offender—and we assess directions for future practices, as well as policy implications.     

Wrangling Rumors of Corruption: Institutional Neutralization of the Jerry Sandusky Scandal at Penn State University

The Jerry Sandusky scandal erupted nationally in November 2011, dragging with it accusations of child molestation, manipulation, perjury, and ultimately a blatant disregard for the suffering of 10 young victims. This article examines how senior university officials covered up the scandal and inevitably allowed Sandusky to continue molesting children for over 15 years. University officials broke the law by failing to report the abuses, and later when they lied to the investigating grand jury assigned to the case. Using Sykes and Matza’s techniques of neutralization, we explain how university officials downplayed these victimizations to preserve the reputation of Penn State.     

Perceived Prevalence and Definitions of Sexual Dysfunction as Predictors of Sexual Function and Satisfaction

Evidence for the influence of sexual beliefs on sexual functioning and satisfaction has mainly emanated from clinical lore. Empirical investigations on this topic remain sparse. This study investigated whether beliefs regarding prevalence and definitions of male and female sexual dysfunctions predicted sexual function and satisfaction in a sample of 131 undergraduate students. Results indicated that higher perceived prevalence of male and female sexual dysfunctions was predictive of lower sexual functioning and poorer sexual satisfaction in women. For the male participants, none of the examined sexual beliefs emerged as significant predictors of their sexual functioning or satisfaction. Surprisingly, it was also found that participants estimated the prevalence of female sexual dysfunctions to be higher than male sexual dysfunctions, while defining male sexual dysfunctions more broadly than female sexual dysfunctions. Possible mechanisms for the findings are provided.     

Motherhood status and union formation in Moshi,Tanzania 2002–2003

Age at first union is increasing throughout much of sub-Saharan Africa at the same time that not all couples are waiting for marriage before their first sexual intercourse. We assessed the effect of a premarital first birth on entrance into a first union in an urban area in East Africa—Moshi, Tanzania. The data come from the Moshi Infertility Survey of 2002–2003. Women who spent less than a year in single motherhood were significantly more likely than childless women to enter into a first union, although the magnitude of this relationship was weaker for more recent cohorts. Women who had been single mothers for 5 or more years (about two-thirds of women with a premarital birth) were significantly less likely than women without children to enter into a first union.     

Vertical foodweb structure of freshwater zooplankton assemblages estimated by stable nitrogen isotopes

Although theoretical foodweb models predict the presence of only three to four trophic categories, estimation of “potential” vertical foodweb structure from species lists and inferred feeding interactions suggest that as many as 7 trophic categories can occur in the pelagic foodwebs of North American glaciated lakes. A compilation of data on the nitrogen isotopic composition of zooplankton from 46 Canadian Shield lakes suggested the average existence of one “realized” trophic category in addition to that of filter-feeding, herbivorous cladocerans. When phytoplankton, planktivorous invertebrates, and plantivorous and piscivorous fish are included, the vertical foodweb structure in the pelagic zones of these lakes are greater than those hypothesized from some theoretical models.     

Demographic change and response: Social context and the practice of birth control in six countries

This paper expands on Kingsley Davis’s demographic thesis of change and response. Specifically, we consider the social context that accounts for the primacy of particular birth control methods that bring about fertility change during specific time periods. We examine the relevance of state policy (including national family planning programs), the international population establishment, the medical profession, organized religion, and women’s groups using case studies from Japan, Russia, Puerto Rico, China, India, and Cameroon. Some of these countries are undergoing the second demographic transition, others the first. Despite variations in context, heavy reliance on sterilization and/or, abortion as a means of birth control is a major response in most of these countries. The key roles of the medical profession and state policy are discussed, along with the general lack of influence of religion and of women’s groups in these countries.     

Migration expectancy revisited: Results for the 1970s, 1980s and 1990s

Planners in a variety of situations require an improved understanding of migration trends if services and products that adequately meet constituent needs are to be provided. This note focuses on changes in migration expectancy over three decades in the context of the planning function. Using the CPS one-year migration question for the periods 1975–1976, 1980–1981, and 1987–1991, and the work of Wilber (1963) and Long (1973) as historical benchmarks, migration expectancy is found to have fallen since the earlier studies. Longer-distance migration (between counties and between states) has remained relatively constant over the same period so that these types of moves now account for a larger proportion of total residential mobility. The results are discussed in the context of their value to individuals and organizations who seek a better understanding of demographically-driven demand from services and products.This article is based on a paper presented at the Southern Demographic Association annual meeting, New Orleans, Louisiana, 22 October 1993.