Numerosity estimates for attended and unattended items in visual search

The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants’ only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.     

The effects of prenatal stress on motivation in the rat pup

Exposure to prenatal stress (PNS) has been shown to induce a set of psychological and behavioral changes in developing offspring. We used the rodent model to investigate whether PNS produces changes in the ability of the pup to express social motivation. We used a set of behavioral tasks including monitoring ultrasonic vocalizations after isolation, a conditioned place preference, and a novel and familiar odor approach test. Pregnant Long-Evans rats were exposed to an unpredictable, variable stressor twice daily during the third week of gestation. Isolation vocalizations were assessed on postnatal day (PND) 10. Pup affinity for the dam was evaluated on PND 15. Typically, pups display a selective preference for an odor-paired environment only after the odor has been associated with the dam. This previous association produces a positive conditioned stimulus (CS). Normally, pups exposed to a neutral CS (odor paired with cotton balls) do not form this place preference. Results indicate that PNS exposed pups had significantly increased distress vocalizations and an equal preference for the positive and neutral conditioned stimuli. This type of alteration in forming early preferences could be detrimental because of decreases in the specificity of social learning and an impaired responsiveness in social relationships.     

Associations Between Family Environment, Parenting Practices, and Executive Functioning of Children with and Without ADHD

We examined the relationships between executive functioning, family environment, and parenting practices in children diagnosed with ADHD as compared to children without ADHD. Participants were parents (N = 134) of 6- to 12-year-old ADHD and non-ADHD-diagnosed children. Compared to the control group, parents of children diagnosed with ADHD reported their children as exhibiting greater problems with behavioral control and metacognitive abilities, and described their family environments as less organized and higher in family conflict. Family environment and parenting practices were not correlated with behavioral control or metacognitive abilities in children with ADHD. In children without ADHD, higher levels of family cohesion, organization, and expressiveness, and lower levels of family conflict, were significantly correlated with greater behavioral control. Higher levels of family cohesion and organization were significantly and positively associated with regulation of metacognitive abilities in children without ADHD. In general, aspects of the family environment and parental limit setting appear to be associated with the development of executive functions in children not diagnosed with ADHD; however, family environment and parenting practices were not associated with executive functions in children diagnosed with ADHD.     

EVALUATION AND TRAINING OF YES‐NO RESPONDING ACROSS VERBAL OPERANTS

Topographically similar verbal responses may be functionally independent forms of operant behavior. For example, saying yes or no may have different functions based on the environmental conditions in effect. The present study extends previous research on both the assessment and acquisition of yes and no responses across contexts in children with language deficits and further examined the functional independence of topographically similar responses. All participants in the present study acquired yes and no responses within verbal operants (e.g., mands). However, generalization of the responses across novel verbal operants (e.g., tacts to intraverbals) did not occur without additional training, thus supporting Skinner's (1957) assertion of functional independence of verbal operants.     

Probabilistically Valid Inference of Covariation From a Single x,y Observation When Univariate Characteristics Are Known

Participants were asked to draw inferences about correlation from single x,y observations. In Experiment 1 statistically sophisticated participants were given the univariate characteristics of distributions of x and y and asked to infer whether a single x, y observation came from a correlated or an uncorrelated population. In Experiment 2, students with a variety of statistical backgrounds assigned posterior probabilities to five possible populations based on single x, y observations, again given knowledge of the univariate statistics. In Experiment 3, statistically naïve participants were given a problem analogous to that given in Experiment 1, framed verbally. Experiment 4 replicated Experiment 3 but added an "impossible to determine" response option. Models that rely on computing sample correlations make no predictions about these investigations. From a Bayesian perspective, participants' inferences in all four experiments tended to make probabilistically valid inferences as long as the single datum was directional. The results are discussed in light of the Brunswikian notion of vicarious functioning.     

Relational aggression and victimization in gay male relationships: the role of internalized homophobia

This article presents two studies that are the first to examine relational aggression and relational victimization in gay male peer relationships. A qualitative pilot study provides a strong rationale for a subsequent empirical investigation of 100 young adult, self-identified gay males. Results of both studies demonstrate that relational aggression and relational victimization are common experiences in gay male relationships. They also reveal forms of relational aggression and victimization that appear to be unique to gay males (e.g., outing). Results of the empirical study found significant relations between engaging in relational aggression against gay males and experiencing relational victimization and between experiencing relational victimization and internalized homophobia. However, there was no significant correlation between internalized homophobia and engaging in relational aggression. A multiple regression analysis found that experiencing relational victimization was correlated more strongly with the combination of engaging in relational aggression and internalized homophobia together than with relational aggression alone. Results are discussed within the framework of Allport's "traits due to victimization" theory and Meyer's theory of "minority stress." Implications for the prevention of relational aggression/victimization in gay male relationships are offered.     

A follow-up study of girls with gender identity disorder

This study provided information on the natural histories of 25 girls with gender identity disorder (GID). Standardized assessment data in childhood (mean age, 8.88 years; range, 3-12 years) and at follow-up (mean age, 23.24 years; range, 15-36 years) were used to evaluate gender identity and sexual orientation. At the assessment in childhood, 60% of the girls met the Diagnostic and Statistical Manual of Mental Disorders criteria for GID, and 40% were subthreshold for the diagnosis. At follow-up, 3 participants (12%) were judged to have GID or gender dysphoria. Regarding sexual orientation, 8 participants (32%) were classified as bisexual/homosexual in fantasy, and 6 (24%) were classified as bisexual/homosexual in behavior. The remaining participants were classified as either heterosexual or asexual. The rates of GID persistence and bisexual/homosexual sexual orientation were substantially higher than base rates in the general female population derived from epidemiological or survey studies. There was some evidence of a "dosage" effect, with girls who were more cross-sex typed in their childhood behavior more likely to be gender dysphoric at follow-up and more likely to have been classified as bisexual/homosexual in behavior (but not in fantasy).     

Infant feeding and HIV in Sub-Saharan Africa: what lies beneath the dilemma?

The debate over how to best guide HIV-infected mothers in resource-poor settings on infant feeding is more than two decades old. Globally, breastfeeding is responsible for approximately 300,000 HIV infections per year, while at the same time, UNICEF estimates that not breastfeeding (formula feeding with contaminated water) is responsible for 1.5 million child deaths per year. The largest burden of these infections and deaths occur in Sub-Saharan Africa. Using this region as an example of the burden faced more generally in other resource-poor settings, we contrast the evolution of the clinical standard of care for infant feeding with HIV-infected mothers in high-income countries to the current international clinical guidelines for HIV-infected mothers and infant feeding in resource-poor settings. While the international guidelines of exclusive breastfeeding for a 6-month period seem to offer the least-worst strategy for reducing mother-to-child transmission of HIV during infancy while conferring some immunity through breastfeeding post-6 months, we argue that the impact of the policy on mothers and healthcare workers on the ground is not well understood. The harm reduction approach on the level of health policy translates into a complicated, painful moral dilemma for HIV-positive mothers and those offering them guidance on infant feeding. We argue that the underlying socio-economic disparities that continue to fuel the need for a harm reduction policy on infant feeding and the harm to women and children justify: (1) that higher priority be given to solving the infant feeding dilemma with improved data on safe feeding alternatives, and (2) support of innovative, community-driven solutions that address the particular economic and cultural challenges that continue to result in HIV-transmission to children within these communities.

Common language effect size for correlations

The Pearson correlation coefficient can be translated to a common language effect size, which shows the probability of obtaining a certain value on one variable, given the value on the other variable. This common language effect size makes the size of a correlation coefficient understandable to laypeople. Three examples are provided to demonstrate the application of the common language effect size in interpreting Pearson correlation coefficients and multiple correlation coefficients.